diff --git a/mfbt/BloomFilter.h b/mfbt/BloomFilter.h
index 26bc043da9c..ec31b60a964 100644
--- a/mfbt/BloomFilter.h
+++ b/mfbt/BloomFilter.h
@@ -133,14 +133,14 @@ public:
      * but will never return false for items that are actually in the
      * filter.
      */
-    bool mayContain(const T* t) const;
+    bool mightContain(const T* t) const;
 
     /*
      * Methods for add/remove/contain when we already have a hash computed
      */
     void add(uint32_t hash);
     void remove(uint32_t hash);
-    bool mayContain(uint32_t hash) const;
+    bool mightContain(uint32_t hash) const;
 
 private:
     static const size_t arraySize = (1 << KeySize);
@@ -213,7 +213,7 @@ BloomFilter<KeySize, T>::remove(const T* t)
 
 template<unsigned KeySize, class T>
 MOZ_ALWAYS_INLINE bool
-BloomFilter<KeySize, T>::mayContain(uint32_t hash) const
+BloomFilter<KeySize, T>::mightContain(uint32_t hash) const
 {
     // Check that all the slots for this hash contain something
     return firstSlot(hash) && secondSlot(hash);
@@ -221,10 +221,10 @@ BloomFilter<KeySize, T>::mayContain(uint32_t hash) const
 
 template<unsigned KeySize, class T>
 MOZ_ALWAYS_INLINE bool
-BloomFilter<KeySize, T>::mayContain(const T* t) const
+BloomFilter<KeySize, T>::mightContain(const T* t) const
 {
     uint32_t hash = t->hash();
-    return mayContain(hash);
+    return mightContain(hash);
 }
 
 } // namespace mozilla
diff --git a/xpcom/tests/TestBloomFilter.cpp b/xpcom/tests/TestBloomFilter.cpp
index f94d5dc6650..7028c0614ec 100644
--- a/xpcom/tests/TestBloomFilter.cpp
+++ b/xpcom/tests/TestBloomFilter.cpp
@@ -32,30 +32,30 @@ int main()
   FilterChecker multiple(0x20001);
 
   filter->add(&one);
-  if (!filter->mayContain(&one)) {
+  if (!filter->mightContain(&one)) {
     fail("Filter should contain 'one'");
     return -1;
   }
 
-  if (filter->mayContain(&multiple)) {
+  if (filter->mightContain(&multiple)) {
     fail("Filter claims to contain 'multiple' when it should not");
     return -1;
   }
 
-  if (!filter->mayContain(&many)) {
+  if (!filter->mightContain(&many)) {
     fail("Filter should contain 'many' (false positive)");
     return -1;
   }
 
   filter->add(&two);
-  if (!filter->mayContain(&multiple)) {
+  if (!filter->mightContain(&multiple)) {
     fail("Filter should contain 'multiple' (false positive)");
     return -1;
   }
 
   // Test basic removals
   filter->remove(&two);
-  if (filter->mayContain(&multiple)) {
+  if (filter->mightContain(&multiple)) {
     fail("Filter claims to contain 'multiple' when it should not after two was "
          "removed");
     return -1;
@@ -66,7 +66,7 @@ int main()
   for (unsigned i = 0; i < FILTER_SIZE - 1; ++i) {
     filter->add(&two);
   }
-  if (!filter->mayContain(&multiple)) {
+  if (!filter->mightContain(&multiple)) {
     fail("Filter should contain 'multiple' after 'two' added lots of times "
          "(false positive)");
     return -1;
@@ -74,7 +74,7 @@ int main()
   for (unsigned i = 0; i < FILTER_SIZE - 1; ++i) {
     filter->remove(&two);
   }
-  if (filter->mayContain(&multiple)) {
+  if (filter->mightContain(&multiple)) {
     fail("Filter claims to contain 'multiple' when it should not after two was "
          "removed lots of times");
     return -1;
@@ -84,7 +84,7 @@ int main()
   for (unsigned i = 0; i < FILTER_SIZE + 1; ++i) {
     filter->add(&two);
   }
-  if (!filter->mayContain(&multiple)) {
+  if (!filter->mightContain(&multiple)) {
     fail("Filter should contain 'multiple' after 'two' added lots more times "
          "(false positive)");
     return -1;
@@ -92,26 +92,26 @@ int main()
   for (unsigned i = 0; i < FILTER_SIZE + 1; ++i) {
     filter->remove(&two);
   }
-  if (!filter->mayContain(&multiple)) {
+  if (!filter->mightContain(&multiple)) {
     fail("Filter claims to not contain 'multiple' even though we should have "
          "run out of space in the buckets (false positive)");
     return -1;
   }
-  if (!filter->mayContain(&two)) {
+  if (!filter->mightContain(&two)) {
     fail("Filter claims to not contain 'two' even though we should have run "
          "out of space in the buckets (false positive)");
     return -1;
   }
 
   filter->remove(&one);
-  if (filter->mayContain(&one)) {
+  if (filter->mightContain(&one)) {
     fail("Filter should not contain 'one', because we didn't overflow its "
          "bucket");
     return -1;
   }
   
   filter->clear();
-  if (filter->mayContain(&multiple)) {
+  if (filter->mightContain(&multiple)) {
     fail("clear() failed to work");
     return -1;
   }