diff --git a/TODO.md b/TODO.md
index 0f0fed4..92c0118 100644
--- a/TODO.md
+++ b/TODO.md
@@ -52,7 +52,7 @@ An important failure of MQL before was that it was never well-specified. Let's n
 ### New Iterators
 
 #### Limit Iterator
-The necessary component to make mid-query limit work. Acts as a limit on Next(), a passthrough on Check(), and a limit on NextResult()
+The necessary component to make mid-query limit work. Acts as a limit on Next(), a passthrough on Contains(), and a limit on NextResult()
 
 ## Medium Term
 
diff --git a/cayley_test.go b/cayley_test.go
index 16a8a3f..af77610 100644
--- a/cayley_test.go
+++ b/cayley_test.go
@@ -86,7 +86,7 @@ var benchmarkQueries = []struct {
 
 	// This is more of an optimization problem that will get better over time. This takes a lot
 	// of wrong turns on the walk down to what is ultimately the name, but top AND has it easy
-	// as it has a fixed ID. Exercises Check().
+	// as it has a fixed ID. Exercises Contains().
 	{
 		message: "the helpless checker",
 		long:    true,
@@ -383,7 +383,7 @@ func BenchmarkVeryLargeSetsSmallIntersection(b *testing.B) {
 	runBench(2, b)
 }
 
-func BenchmarkHelplessChecker(b *testing.B) {
+func BenchmarkHelplessContainsChecker(b *testing.B) {
 	runBench(3, b)
 }
 
diff --git a/graph/iterator.go b/graph/iterator.go
index d28f43e..972f334 100644
--- a/graph/iterator.go
+++ b/graph/iterator.go
@@ -89,9 +89,8 @@ type Iterator interface {
 	// from the bottom up.
 	NextResult() bool
 
-	// Check(), given a value, returns whether or not that value is within the set
-	// held by this iterator.
-	Check(Value) bool
+	// Contains returns whether the value is within the set held by the iterator.
+	Contains(Value) bool
 
 	// Start iteration from the beginning
 	Reset()
@@ -161,9 +160,9 @@ type FixedIterator interface {
 }
 
 type IteratorStats struct {
-	CheckCost int64
-	NextCost  int64
-	Size      int64
+	ContainsCost int64
+	NextCost     int64
+	Size         int64
 }
 
 // Type enumerates the set of Iterator types.
@@ -229,20 +228,20 @@ func (t Type) String() string {
 	return types[t]
 }
 
-// Utility logging functions for when an iterator gets called Next upon, or Check upon, as
+// Utility logging functions for when an iterator gets called Next upon, or Contains upon, as
 // well as what they return. Highly useful for tracing the execution path of a query.
-func CheckLogIn(it Iterator, val Value) {
+func ContainsLogIn(it Iterator, val Value) {
 	if glog.V(4) {
-		glog.V(4).Infof("%s %d CHECK %d", strings.ToUpper(it.Type().String()), it.UID(), val)
+		glog.V(4).Infof("%s %d CHECK CONTAINS %d", strings.ToUpper(it.Type().String()), it.UID(), val)
 	}
 }
 
-func CheckLogOut(it Iterator, val Value, good bool) bool {
+func ContainsLogOut(it Iterator, val Value, good bool) bool {
 	if glog.V(4) {
 		if good {
-			glog.V(4).Infof("%s %d CHECK %d GOOD", strings.ToUpper(it.Type().String()), it.UID(), val)
+			glog.V(4).Infof("%s %d CHECK CONTAINS %d GOOD", strings.ToUpper(it.Type().String()), it.UID(), val)
 		} else {
-			glog.V(4).Infof("%s %d CHECK %d BAD", strings.ToUpper(it.Type().String()), it.UID(), val)
+			glog.V(4).Infof("%s %d CHECK CONTAINS %d BAD", strings.ToUpper(it.Type().String()), it.UID(), val)
 		}
 	}
 	return good
diff --git a/graph/iterator/all_iterator.go b/graph/iterator/all_iterator.go
index ff1a869..a3e1174 100644
--- a/graph/iterator/all_iterator.go
+++ b/graph/iterator/all_iterator.go
@@ -126,16 +126,16 @@ func (it *Int64) Size() (int64, bool) {
 	return Size, true
 }
 
-// Check() for an Int64 is merely seeing if the passed value is
+// Contains() for an Int64 is merely seeing if the passed value is
 // withing the range, assuming the value is an int64.
-func (it *Int64) Check(tsv graph.Value) bool {
-	graph.CheckLogIn(it, tsv)
+func (it *Int64) Contains(tsv graph.Value) bool {
+	graph.ContainsLogIn(it, tsv)
 	v := tsv.(int64)
 	if it.min <= v && v <= it.max {
 		it.result = v
-		return graph.CheckLogOut(it, v, true)
+		return graph.ContainsLogOut(it, v, true)
 	}
-	return graph.CheckLogOut(it, v, false)
+	return graph.ContainsLogOut(it, v, false)
 }
 
 // The type of this iterator is an "all". This is important, as it puts it in
@@ -150,8 +150,8 @@ func (it *Int64) Optimize() (graph.Iterator, bool) { return it, false }
 func (it *Int64) Stats() graph.IteratorStats {
 	s, _ := it.Size()
 	return graph.IteratorStats{
-		CheckCost: 1,
-		NextCost:  1,
-		Size:      s,
+		ContainsCost: 1,
+		NextCost:     1,
+		Size:         s,
 	}
 }
diff --git a/graph/iterator/and_iterator.go b/graph/iterator/and_iterator.go
index 902b9a1..654f7c6 100644
--- a/graph/iterator/and_iterator.go
+++ b/graph/iterator/and_iterator.go
@@ -6,11 +6,11 @@
 //
 // It accomplishes this in one of two ways. If it is a Next()ed iterator (that
 // is, it is a top level iterator, or on the "Next() path", then it will Next()
-// it's primary iterator (helpfully, and.primary_it) and Check() the resultant
+// it's primary iterator (helpfully, and.primary_it) and Contains() the resultant
 // value against it's other iterators. If it matches all of them, then it
 // returns that value. Otherwise, it repeats the process.
 //
-// If it's on a Check() path, it merely Check()s every iterator, and returns the
+// If it's on a Contains() path, it merely Contains()s every iterator, and returns the
 // logical AND of each result.
 
 package iterator
@@ -86,7 +86,7 @@ func (it *And) Clone() graph.Iterator {
 		and.AddSubIterator(sub.Clone())
 	}
 	if it.checkList != nil {
-		and.optimizeCheck()
+		and.optimizeContains()
 	}
 	return and
 }
@@ -164,7 +164,7 @@ func (it *And) Next() (graph.Value, bool) {
 		if !exists {
 			return graph.NextLogOut(it, nil, false)
 		}
-		if it.checkSubIts(curr) {
+		if it.subItsContain(curr) {
 			it.result = curr
 			return graph.NextLogOut(it, curr, true)
 		}
@@ -177,10 +177,10 @@ func (it *And) Result() graph.Value {
 }
 
 // Checks a value against the non-primary iterators, in order.
-func (it *And) checkSubIts(val graph.Value) bool {
+func (it *And) subItsContain(val graph.Value) bool {
 	var subIsGood = true
 	for _, sub := range it.internalIterators {
-		subIsGood = sub.Check(val)
+		subIsGood = sub.Contains(val)
 		if !subIsGood {
 			break
 		}
@@ -188,10 +188,10 @@ func (it *And) checkSubIts(val graph.Value) bool {
 	return subIsGood
 }
 
-func (it *And) checkCheckList(val graph.Value) bool {
+func (it *And) checkContainsList(val graph.Value) bool {
 	ok := true
 	for _, c := range it.checkList {
-		ok = c.Check(val)
+		ok = c.Contains(val)
 		if !ok {
 			break
 		}
@@ -199,25 +199,25 @@ func (it *And) checkCheckList(val graph.Value) bool {
 	if ok {
 		it.result = val
 	}
-	return graph.CheckLogOut(it, val, ok)
+	return graph.ContainsLogOut(it, val, ok)
 }
 
 // Check a value against the entire iterator, in order.
-func (it *And) Check(val graph.Value) bool {
-	graph.CheckLogIn(it, val)
+func (it *And) Contains(val graph.Value) bool {
+	graph.ContainsLogIn(it, val)
 	if it.checkList != nil {
-		return it.checkCheckList(val)
+		return it.checkContainsList(val)
 	}
-	mainGood := it.primaryIt.Check(val)
+	mainGood := it.primaryIt.Contains(val)
 	if !mainGood {
-		return graph.CheckLogOut(it, val, false)
+		return graph.ContainsLogOut(it, val, false)
 	}
-	othersGood := it.checkSubIts(val)
+	othersGood := it.subItsContain(val)
 	if !othersGood {
-		return graph.CheckLogOut(it, val, false)
+		return graph.ContainsLogOut(it, val, false)
 	}
 	it.result = val
-	return graph.CheckLogOut(it, val, true)
+	return graph.ContainsLogOut(it, val, true)
 }
 
 // Returns the approximate size of the And iterator. Because we're dealing
diff --git a/graph/iterator/and_iterator_optimize.go b/graph/iterator/and_iterator_optimize.go
index 20a4771..92b6b41 100644
--- a/graph/iterator/and_iterator_optimize.go
+++ b/graph/iterator/and_iterator_optimize.go
@@ -38,10 +38,10 @@ import (
 // In short, tread lightly.
 
 // Optimizes the And, by picking the most efficient way to Next() and
-// Check() its subiterators. For SQL fans, this is equivalent to JOIN.
+// Contains() its subiterators. For SQL fans, this is equivalent to JOIN.
 func (it *And) Optimize() (graph.Iterator, bool) {
 	// First, let's get the slice of iterators, in order (first one is Next()ed,
-	// the rest are Check()ed)
+	// the rest are Contains()ed)
 	old := it.SubIterators()
 
 	// And call Optimize() on our subtree, replacing each one in the order we
@@ -84,7 +84,7 @@ func (it *And) Optimize() (graph.Iterator, bool) {
 	// Move the tags hanging on us (like any good replacement).
 	newAnd.tags.CopyFrom(it)
 
-	newAnd.optimizeCheck()
+	newAnd.optimizeContains()
 
 	// And close ourselves but not our subiterators -- some may still be alive in
 	// the new And (they were unchanged upon calling Optimize() on them, at the
@@ -142,7 +142,7 @@ func optimizeOrder(its []graph.Iterator) []graph.Iterator {
 
 	// Find the iterator with the projected "best" total cost.
 	// Total cost is defined as The Next()ed iterator's cost to Next() out
-	// all of it's contents, and to Check() each of those against everyone
+	// all of it's contents, and to Contains() each of those against everyone
 	// else.
 	for _, it := range its {
 		if _, canNext := it.(graph.Nexter); !canNext {
@@ -159,7 +159,7 @@ func optimizeOrder(its []graph.Iterator) []graph.Iterator {
 				continue
 			}
 			stats := f.Stats()
-			cost += stats.CheckCost
+			cost += stats.ContainsCost
 		}
 		cost *= rootStats.Size
 		if cost < bestCost {
@@ -169,7 +169,7 @@ func optimizeOrder(its []graph.Iterator) []graph.Iterator {
 	}
 
 	// TODO(barakmich): Optimization of order need not stop here. Picking a smart
-	// Check() order based on probability of getting a false Check() first is
+	// Contains() order based on probability of getting a false Contains() first is
 	// useful (fail faster).
 
 	// Put the best iterator (the one we wish to Next()) at the front...
@@ -192,12 +192,12 @@ func optimizeOrder(its []graph.Iterator) []graph.Iterator {
 type byCost []graph.Iterator
 
 func (c byCost) Len() int           { return len(c) }
-func (c byCost) Less(i, j int) bool { return c[i].Stats().CheckCost < c[j].Stats().CheckCost }
+func (c byCost) Less(i, j int) bool { return c[i].Stats().ContainsCost < c[j].Stats().ContainsCost }
 func (c byCost) Swap(i, j int)      { c[i], c[j] = c[j], c[i] }
 
-// optimizeCheck(l) creates an alternate check list, containing the same contents
+// optimizeContains() creates an alternate check list, containing the same contents
 // but with a new ordering, however it wishes.
-func (it *And) optimizeCheck() {
+func (it *And) optimizeContains() {
 	// GetSubIterators allocates, so this is currently safe.
 	// TODO(kortschak) Reuse it.checkList if possible.
 	// This involves providing GetSubIterators with a slice to fill.
@@ -298,21 +298,21 @@ func hasOneUsefulIterator(its []graph.Iterator) graph.Iterator {
 // For now, however, it's pretty static.
 func (it *And) Stats() graph.IteratorStats {
 	primaryStats := it.primaryIt.Stats()
-	CheckCost := primaryStats.CheckCost
+	ContainsCost := primaryStats.ContainsCost
 	NextCost := primaryStats.NextCost
 	Size := primaryStats.Size
 	for _, sub := range it.internalIterators {
 		stats := sub.Stats()
-		NextCost += stats.CheckCost
-		CheckCost += stats.CheckCost
+		NextCost += stats.ContainsCost
+		ContainsCost += stats.ContainsCost
 		if Size > stats.Size {
 			Size = stats.Size
 		}
 	}
 	return graph.IteratorStats{
-		CheckCost: CheckCost,
-		NextCost:  NextCost,
-		Size:      Size,
+		ContainsCost: ContainsCost,
+		NextCost:     NextCost,
+		Size:         Size,
 	}
 
 }
diff --git a/graph/iterator/fixed_iterator.go b/graph/iterator/fixed_iterator.go
index 6bfebb5..7efee2d 100644
--- a/graph/iterator/fixed_iterator.go
+++ b/graph/iterator/fixed_iterator.go
@@ -121,18 +121,18 @@ func (it *Fixed) DebugString(indent int) string {
 func (it *Fixed) Type() graph.Type { return graph.Fixed }
 
 // Check if the passed value is equal to one of the values stored in the iterator.
-func (it *Fixed) Check(v graph.Value) bool {
+func (it *Fixed) Contains(v graph.Value) bool {
 	// Could be optimized by keeping it sorted or using a better datastructure.
 	// However, for fixed iterators, which are by definition kind of tiny, this
 	// isn't a big issue.
-	graph.CheckLogIn(it, v)
+	graph.ContainsLogIn(it, v)
 	for _, x := range it.values {
 		if it.cmp(x, v) {
 			it.result = x
-			return graph.CheckLogOut(it, v, true)
+			return graph.ContainsLogOut(it, v, true)
 		}
 	}
-	return graph.CheckLogOut(it, v, false)
+	return graph.ContainsLogOut(it, v, false)
 }
 
 // Return the next stored value from the iterator.
@@ -181,12 +181,12 @@ func (it *Fixed) Size() (int64, bool) {
 	return int64(len(it.values)), true
 }
 
-// As we right now have to scan the entire list, Next and Check are linear with the
+// As we right now have to scan the entire list, Next and Contains are linear with the
 // size. However, a better data structure could remove these limits.
 func (it *Fixed) Stats() graph.IteratorStats {
 	return graph.IteratorStats{
-		CheckCost: int64(len(it.values)),
-		NextCost:  int64(len(it.values)),
-		Size:      int64(len(it.values)),
+		ContainsCost: int64(len(it.values)),
+		NextCost:     int64(len(it.values)),
+		Size:         int64(len(it.values)),
 	}
 }
diff --git a/graph/iterator/hasa_iterator.go b/graph/iterator/hasa_iterator.go
index 2a0b46c..954102a 100644
--- a/graph/iterator/hasa_iterator.go
+++ b/graph/iterator/hasa_iterator.go
@@ -23,10 +23,10 @@ package iterator
 // path. That's okay -- in reality, it can be viewed as returning the value for
 // a new triple, but to make logic much simpler, here we have the HasA.
 //
-// Likewise, it's important to think about Check()ing a HasA. When given a
+// Likewise, it's important to think about Contains()ing a HasA. When given a
 // value to check, it means "Check all predicates that have this value for your
 // direction against the subiterator." This would imply that there's more than
-// one possibility for the same Check()ed value. While we could return the
+// one possibility for the same Contains()ed value. While we could return the
 // number of options, it's simpler to return one, and then call NextResult()
 // enough times to enumerate the options. (In fact, one could argue that the
 // raison d'etre for NextResult() is this iterator).
@@ -45,7 +45,7 @@ import (
 
 // A HasA consists of a reference back to the graph.TripleStore that it references,
 // a primary subiterator, a direction in which the triples for that subiterator point,
-// and a temporary holder for the iterator generated on Check().
+// and a temporary holder for the iterator generated on Contains().
 type HasA struct {
 	uid       uint64
 	tags      graph.Tagger
@@ -140,9 +140,9 @@ func (it *HasA) DebugString(indent int) string {
 
 // Check a value against our internal iterator. In order to do this, we must first open a new
 // iterator of "triples that have `val` in our direction", given to us by the triple store,
-// and then Next() values out of that iterator and Check() them against our subiterator.
-func (it *HasA) Check(val graph.Value) bool {
-	graph.CheckLogIn(it, val)
+// and then Next() values out of that iterator and Contains() them against our subiterator.
+func (it *HasA) Contains(val graph.Value) bool {
+	graph.ContainsLogIn(it, val)
 	if glog.V(4) {
 		glog.V(4).Infoln("Id is", it.ts.NameOf(val))
 	}
@@ -151,13 +151,13 @@ func (it *HasA) Check(val graph.Value) bool {
 		it.resultIt.Close()
 	}
 	it.resultIt = it.ts.TripleIterator(it.dir, val)
-	return graph.CheckLogOut(it, val, it.GetCheckResult())
+	return graph.ContainsLogOut(it, val, it.NextContains())
 }
 
-// GetCheckResult() is shared code between Check() and GetNextResult() -- calls next on the
+// NextContains() is shared code between Contains() and GetNextResult() -- calls next on the
 // result iterator (a triple iterator based on the last checked value) and returns true if
 // another match is made.
-func (it *HasA) GetCheckResult() bool {
+func (it *HasA) NextContains() bool {
 	for {
 		linkVal, ok := graph.Next(it.resultIt)
 		if !ok {
@@ -166,7 +166,7 @@ func (it *HasA) GetCheckResult() bool {
 		if glog.V(4) {
 			glog.V(4).Infoln("Quad is", it.ts.Quad(linkVal))
 		}
-		if it.primaryIt.Check(linkVal) {
+		if it.primaryIt.Contains(linkVal) {
 			it.result = it.ts.TripleDirection(linkVal, it.dir)
 			return true
 		}
@@ -178,17 +178,17 @@ func (it *HasA) GetCheckResult() bool {
 func (it *HasA) NextResult() bool {
 	// Order here is important. If the subiterator has a NextResult, then we
 	// need do nothing -- there is a next result, and we shouldn't move forward.
-	// However, we then need to get the next result from our last Check().
+	// However, we then need to get the next result from our last Contains().
 	//
 	// The upshot is, the end of NextResult() bubbles up from the bottom of the
 	// iterator tree up, and we need to respect that.
 	if it.primaryIt.NextResult() {
 		return true
 	}
-	return it.GetCheckResult()
+	return it.NextContains()
 }
 
-// Get the next result from this iterator. This is simpler than Check. We have a
+// Get the next result from this iterator. This is simpler than Contains. We have a
 // subiterator we can get a value from, and we can take that resultant triple,
 // pull our direction out of it, and return that.
 func (it *HasA) Next() (graph.Value, bool) {
@@ -214,7 +214,7 @@ func (it *HasA) Result() graph.Value {
 
 // GetStats() returns the statistics on the HasA iterator. This is curious. Next
 // cost is easy, it's an extra call or so on top of the subiterator Next cost.
-// CheckCost involves going to the graph.TripleStore, iterating out values, and hoping
+// ContainsCost involves going to the graph.TripleStore, iterating out values, and hoping
 // one sticks -- potentially expensive, depending on fanout. Size, however, is
 // potentially smaller. we know at worst it's the size of the subiterator, but
 // if there are many repeated values, it could be much smaller in totality.
@@ -227,9 +227,9 @@ func (it *HasA) Stats() graph.IteratorStats {
 	nextConstant := int64(2)
 	tripleConstant := int64(1)
 	return graph.IteratorStats{
-		NextCost:  tripleConstant + subitStats.NextCost,
-		CheckCost: (fanoutFactor * nextConstant) * subitStats.CheckCost,
-		Size:      faninFactor * subitStats.Size,
+		NextCost:     tripleConstant + subitStats.NextCost,
+		ContainsCost: (fanoutFactor * nextConstant) * subitStats.ContainsCost,
+		Size:         faninFactor * subitStats.Size,
 	}
 }
 
diff --git a/graph/iterator/iterator.go b/graph/iterator/iterator.go
index e80b56c..69b26c5 100644
--- a/graph/iterator/iterator.go
+++ b/graph/iterator/iterator.go
@@ -61,7 +61,7 @@ func (it *Null) TagResults(dst map[string]graph.Value) {
 	}
 }
 
-func (it *Null) Check(graph.Value) bool {
+func (it *Null) Contains(graph.Value) bool {
 	return false
 }
 
diff --git a/graph/iterator/linksto_iterator.go b/graph/iterator/linksto_iterator.go
index 9ad81d6..a79b34b 100644
--- a/graph/iterator/linksto_iterator.go
+++ b/graph/iterator/linksto_iterator.go
@@ -23,7 +23,7 @@ package iterator
 // LinksTo is therefore sensitive to growing with a fanout. (A small-sized
 // subiterator could cause LinksTo to be large).
 //
-// Check()ing a LinksTo means, given a link, take the direction we care about
+// Contains()ing a LinksTo means, given a link, take the direction we care about
 // and check if it's in our subiterator. Checking is therefore fairly cheap, and
 // similar to checking the subiterator alone.
 //
@@ -116,14 +116,14 @@ func (it *LinksTo) DebugString(indent int) string {
 
 // If it checks in the right direction for the subiterator, it is a valid link
 // for the LinksTo.
-func (it *LinksTo) Check(val graph.Value) bool {
-	graph.CheckLogIn(it, val)
+func (it *LinksTo) Contains(val graph.Value) bool {
+	graph.ContainsLogIn(it, val)
 	node := it.ts.TripleDirection(val, it.dir)
-	if it.primaryIt.Check(node) {
+	if it.primaryIt.Contains(node) {
 		it.result = val
-		return graph.CheckLogOut(it, val, true)
+		return graph.ContainsLogOut(it, val, true)
 	}
-	return graph.CheckLogOut(it, val, false)
+	return graph.ContainsLogOut(it, val, false)
 }
 
 // Return a list containing only our subiterator.
@@ -198,9 +198,9 @@ func (it *LinksTo) Stats() graph.IteratorStats {
 	checkConstant := int64(1)
 	nextConstant := int64(2)
 	return graph.IteratorStats{
-		NextCost:  nextConstant + subitStats.NextCost,
-		CheckCost: checkConstant + subitStats.CheckCost,
-		Size:      fanoutFactor * subitStats.Size,
+		NextCost:     nextConstant + subitStats.NextCost,
+		ContainsCost: checkConstant + subitStats.ContainsCost,
+		Size:         fanoutFactor * subitStats.Size,
 	}
 }
 
diff --git a/graph/iterator/optional_iterator.go b/graph/iterator/optional_iterator.go
index bc6899c..646bc7f 100644
--- a/graph/iterator/optional_iterator.go
+++ b/graph/iterator/optional_iterator.go
@@ -100,11 +100,11 @@ func (it *Optional) SubIterators() []graph.Iterator {
 	return nil
 }
 
-// Check() is the real hack of this iterator. It always returns true, regardless
+// Contains() is the real hack of this iterator. It always returns true, regardless
 // of whether the subiterator matched. But we keep track of whether the subiterator
 // matched for results purposes.
-func (it *Optional) Check(val graph.Value) bool {
-	checked := it.subIt.Check(val)
+func (it *Optional) Contains(val graph.Value) bool {
+	checked := it.subIt.Contains(val)
 	it.lastCheck = checked
 	it.result = val
 	return true
@@ -146,9 +146,9 @@ func (it *Optional) Optimize() (graph.Iterator, bool) {
 func (it *Optional) Stats() graph.IteratorStats {
 	subStats := it.subIt.Stats()
 	return graph.IteratorStats{
-		CheckCost: subStats.CheckCost,
-		NextCost:  int64(1 << 62),
-		Size:      subStats.Size,
+		ContainsCost: subStats.ContainsCost,
+		NextCost:     int64(1 << 62),
+		Size:         subStats.Size,
 	}
 }
 
diff --git a/graph/iterator/or_iterator.go b/graph/iterator/or_iterator.go
index 13f28b8..b7e765a 100644
--- a/graph/iterator/or_iterator.go
+++ b/graph/iterator/or_iterator.go
@@ -177,10 +177,10 @@ func (it *Or) Result() graph.Value {
 }
 
 // Checks a value against the iterators, in order.
-func (it *Or) checkSubIts(val graph.Value) bool {
+func (it *Or) subItsContain(val graph.Value) bool {
 	var subIsGood = false
 	for i, sub := range it.internalIterators {
-		subIsGood = sub.Check(val)
+		subIsGood = sub.Contains(val)
 		if subIsGood {
 			it.currentIterator = i
 			break
@@ -190,14 +190,14 @@ func (it *Or) checkSubIts(val graph.Value) bool {
 }
 
 // Check a value against the entire graph.iterator, in order.
-func (it *Or) Check(val graph.Value) bool {
-	graph.CheckLogIn(it, val)
-	anyGood := it.checkSubIts(val)
+func (it *Or) Contains(val graph.Value) bool {
+	graph.ContainsLogIn(it, val)
+	anyGood := it.subItsContain(val)
 	if !anyGood {
-		return graph.CheckLogOut(it, val, false)
+		return graph.ContainsLogOut(it, val, false)
 	}
 	it.result = val
-	return graph.CheckLogOut(it, val, true)
+	return graph.ContainsLogOut(it, val, true)
 }
 
 // Returns the approximate size of the Or graph.iterator. Because we're dealing
@@ -277,13 +277,13 @@ func (it *Or) Optimize() (graph.Iterator, bool) {
 }
 
 func (it *Or) Stats() graph.IteratorStats {
-	CheckCost := int64(0)
+	ContainsCost := int64(0)
 	NextCost := int64(0)
 	Size := int64(0)
 	for _, sub := range it.internalIterators {
 		stats := sub.Stats()
 		NextCost += stats.NextCost
-		CheckCost += stats.CheckCost
+		ContainsCost += stats.ContainsCost
 		if it.isShortCircuiting {
 			if Size < stats.Size {
 				Size = stats.Size
@@ -293,9 +293,9 @@ func (it *Or) Stats() graph.IteratorStats {
 		}
 	}
 	return graph.IteratorStats{
-		CheckCost: CheckCost,
-		NextCost:  NextCost,
-		Size:      Size,
+		ContainsCost: ContainsCost,
+		NextCost:     NextCost,
+		Size:         Size,
 	}
 
 }
diff --git a/graph/iterator/or_iterator_test.go b/graph/iterator/or_iterator_test.go
index 78742eb..bbd5de6 100644
--- a/graph/iterator/or_iterator_test.go
+++ b/graph/iterator/or_iterator_test.go
@@ -66,13 +66,13 @@ func TestOrIteratorBasics(t *testing.T) {
 	}
 
 	for _, v := range []int{2, 3, 21} {
-		if !or.Check(v) {
+		if !or.Contains(v) {
 			t.Errorf("Failed to correctly check %d as true", v)
 		}
 	}
 
 	for _, v := range []int{22, 5, 0} {
-		if or.Check(v) {
+		if or.Contains(v) {
 			t.Errorf("Failed to correctly check %d as false", v)
 		}
 	}
@@ -125,12 +125,12 @@ func TestShortCircuitingOrBasics(t *testing.T) {
 	or.AddSubIterator(f1)
 	or.AddSubIterator(f2)
 	for _, v := range []int{2, 3, 21} {
-		if !or.Check(v) {
+		if !or.Contains(v) {
 			t.Errorf("Failed to correctly check %d as true", v)
 		}
 	}
 	for _, v := range []int{22, 5, 0} {
-		if or.Check(v) {
+		if or.Contains(v) {
 			t.Errorf("Failed to correctly check %d as false", v)
 		}
 	}
diff --git a/graph/iterator/value_comparison_iterator.go b/graph/iterator/value_comparison_iterator.go
index 7d687bd..7c2eb58 100644
--- a/graph/iterator/value_comparison_iterator.go
+++ b/graph/iterator/value_comparison_iterator.go
@@ -171,11 +171,11 @@ func (it *Comparison) SubIterators() []graph.Iterator {
 	return nil
 }
 
-func (it *Comparison) Check(val graph.Value) bool {
+func (it *Comparison) Contains(val graph.Value) bool {
 	if !it.doComparison(val) {
 		return false
 	}
-	return it.subIt.Check(val)
+	return it.subIt.Contains(val)
 }
 
 // If we failed the check, then the subiterator should not contribute to the result
diff --git a/graph/iterator/value_comparison_iterator_test.go b/graph/iterator/value_comparison_iterator_test.go
index 2c605ec..e7482e8 100644
--- a/graph/iterator/value_comparison_iterator_test.go
+++ b/graph/iterator/value_comparison_iterator_test.go
@@ -82,7 +82,7 @@ func TestValueComparison(t *testing.T) {
 	}
 }
 
-var vciCheckTests = []struct {
+var vciContainsTests = []struct {
 	message  string
 	operator Operator
 	check    graph.Value
@@ -114,10 +114,10 @@ var vciCheckTests = []struct {
 	},
 }
 
-func TestVCICheck(t *testing.T) {
-	for _, test := range vciCheckTests {
+func TestVCIContains(t *testing.T) {
+	for _, test := range vciContainsTests {
 		vc := NewComparison(simpleFixedIterator(), test.operator, int64(2), simpleStore)
-		if vc.Check(test.check) != test.expect {
+		if vc.Contains(test.check) != test.expect {
 			t.Errorf("Failed to show %s", test.message)
 		}
 	}
diff --git a/graph/leveldb/all_iterator.go b/graph/leveldb/all_iterator.go
index b45fc0d..5346f97 100644
--- a/graph/leveldb/all_iterator.go
+++ b/graph/leveldb/all_iterator.go
@@ -138,7 +138,7 @@ func (it *AllIterator) SubIterators() []graph.Iterator {
 	return nil
 }
 
-func (it *AllIterator) Check(v graph.Value) bool {
+func (it *AllIterator) Contains(v graph.Value) bool {
 	it.result = v
 	return true
 }
@@ -174,8 +174,8 @@ func (it *AllIterator) Optimize() (graph.Iterator, bool) {
 func (it *AllIterator) Stats() graph.IteratorStats {
 	s, _ := it.Size()
 	return graph.IteratorStats{
-		CheckCost: 1,
-		NextCost:  2,
-		Size:      s,
+		ContainsCost: 1,
+		NextCost:     2,
+		Size:         s,
 	}
 }
diff --git a/graph/leveldb/iterator.go b/graph/leveldb/iterator.go
index 51bce4c..b434dfd 100644
--- a/graph/leveldb/iterator.go
+++ b/graph/leveldb/iterator.go
@@ -215,7 +215,7 @@ func PositionOf(prefix []byte, d quad.Direction, qs *TripleStore) int {
 	panic("unreachable")
 }
 
-func (it *Iterator) Check(v graph.Value) bool {
+func (it *Iterator) Contains(v graph.Value) bool {
 	val := v.([]byte)
 	if val[0] == 'z' {
 		return false
@@ -262,8 +262,8 @@ func (it *Iterator) Optimize() (graph.Iterator, bool) {
 func (it *Iterator) Stats() graph.IteratorStats {
 	s, _ := it.Size()
 	return graph.IteratorStats{
-		CheckCost: 1,
-		NextCost:  2,
-		Size:      s,
+		ContainsCost: 1,
+		NextCost:     2,
+		Size:         s,
 	}
 }
diff --git a/graph/leveldb/leveldb_test.go b/graph/leveldb/leveldb_test.go
index bba1eb8..0e6772a 100644
--- a/graph/leveldb/leveldb_test.go
+++ b/graph/leveldb/leveldb_test.go
@@ -251,14 +251,14 @@ func TestIterator(t *testing.T) {
 	}
 
 	for _, pq := range expect {
-		if !it.Check(qs.ValueOf(pq)) {
+		if !it.Contains(qs.ValueOf(pq)) {
 			t.Errorf("Failed to find and check %q correctly", pq)
 		}
 	}
 	// FIXME(kortschak) Why does this fail?
 	/*
 		for _, pq := range []string{"baller"} {
-			if it.Check(qs.ValueOf(pq)) {
+			if it.Contains(qs.ValueOf(pq)) {
 				t.Errorf("Failed to check %q correctly", pq)
 			}
 		}
diff --git a/graph/memstore/iterator.go b/graph/memstore/iterator.go
index 7ec913a..8a7e1ef 100644
--- a/graph/memstore/iterator.go
+++ b/graph/memstore/iterator.go
@@ -124,13 +124,13 @@ func (it *Iterator) Size() (int64, bool) {
 	return int64(it.tree.Len()), true
 }
 
-func (it *Iterator) Check(v graph.Value) bool {
-	graph.CheckLogIn(it, v)
+func (it *Iterator) Contains(v graph.Value) bool {
+	graph.ContainsLogIn(it, v)
 	if it.tree.Has(Int64(v.(int64))) {
 		it.result = v
-		return graph.CheckLogOut(it, v, true)
+		return graph.ContainsLogOut(it, v, true)
 	}
-	return graph.CheckLogOut(it, v, false)
+	return graph.ContainsLogOut(it, v, false)
 }
 
 func (it *Iterator) DebugString(indent int) string {
@@ -156,8 +156,8 @@ func (it *Iterator) Optimize() (graph.Iterator, bool) {
 
 func (it *Iterator) Stats() graph.IteratorStats {
 	return graph.IteratorStats{
-		CheckCost: int64(math.Log(float64(it.tree.Len()))) + 1,
-		NextCost:  1,
-		Size:      int64(it.tree.Len()),
+		ContainsCost: int64(math.Log(float64(it.tree.Len()))) + 1,
+		NextCost:     1,
+		Size:         int64(it.tree.Len()),
 	}
 }
diff --git a/graph/mongo/iterator.go b/graph/mongo/iterator.go
index d04c8fa..f9cea5b 100644
--- a/graph/mongo/iterator.go
+++ b/graph/mongo/iterator.go
@@ -174,11 +174,11 @@ func (it *Iterator) SubIterators() []graph.Iterator {
 	return nil
 }
 
-func (it *Iterator) Check(v graph.Value) bool {
-	graph.CheckLogIn(it, v)
+func (it *Iterator) Contains(v graph.Value) bool {
+	graph.ContainsLogIn(it, v)
 	if it.isAll {
 		it.result = v
-		return graph.CheckLogOut(it, v, true)
+		return graph.ContainsLogOut(it, v, true)
 	}
 	var offset int
 	switch it.dir {
@@ -194,9 +194,9 @@ func (it *Iterator) Check(v graph.Value) bool {
 	val := v.(string)[offset : it.qs.hasher.Size()*2+offset]
 	if val == it.hash {
 		it.result = v
-		return graph.CheckLogOut(it, v, true)
+		return graph.ContainsLogOut(it, v, true)
 	}
-	return graph.CheckLogOut(it, v, false)
+	return graph.ContainsLogOut(it, v, false)
 }
 
 func (it *Iterator) Size() (int64, bool) {
@@ -229,8 +229,8 @@ func (it *Iterator) DebugString(indent int) string {
 func (it *Iterator) Stats() graph.IteratorStats {
 	size, _ := it.Size()
 	return graph.IteratorStats{
-		CheckCost: 1,
-		NextCost:  5,
-		Size:      size,
+		ContainsCost: 1,
+		NextCost:     5,
+		Size:         size,
 	}
 }