--- a/ipc/glue/SharedMemory.h
+++ b/ipc/glue/SharedMemory.h
@@ -116,19 +116,19 @@ protected:
   //
   // but this isn't checked.
   void Created(size_t aNBytes);
   void Mapped(size_t aNBytes);
   void Unmapped();
   void Destroyed();
 
   // The size of the shmem region requested in Create(), if
-  // successful.  SharedMemorys that are opened from a foreign handle
-  // have an alloc size of 0, even though they have access to the
-  // alloc-size information.
+  // successful.  SharedMemory instances that are opened from a
+  // foreign handle have an alloc size of 0, even though they have
+  // access to the alloc-size information.
   size_t mAllocSize;
   // The size of the region mapped in Map(), if successful.  All
   // SharedMemorys that are mapped have a non-zero mapped size.
   size_t mMappedSize;
 };
 
 } // namespace ipc
 } // namespace mozilla