diff --git a/src/libcollections/btree/set.rs b/src/libcollections/btree/set.rs
index 49da3aa480c..fc2a7f82547 100644
--- a/src/libcollections/btree/set.rs
+++ b/src/libcollections/btree/set.rs
@@ -674,7 +674,7 @@ impl<'a, T: 'a + Ord + Copy> Extend<&'a T> for BTreeSet<T> {
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T: Ord> Default for BTreeSet<T> {
-    /// Makes a empty `BTreeSet<T>` with a reasonable choice of B.
+    /// Makes an empty `BTreeSet<T>` with a reasonable choice of B.
     fn default() -> BTreeSet<T> {
         BTreeSet::new()
     }