diff --git a/src/libcore/marker.rs b/src/libcore/marker.rs
index f32552f300c..688f0484401 100644
--- a/src/libcore/marker.rs
+++ b/src/libcore/marker.rs
@@ -27,7 +27,7 @@
 
 use clone::Clone;
 
-/// Types able to be transferred across task boundaries.
+/// Types able to be transferred across thread boundaries.
 #[unstable = "will be overhauled with new lifetime rules; see RFC 458"]
 #[lang="send"]
 #[rustc_on_unimplemented = "`{Self}` cannot be sent between threads safely"]
@@ -148,11 +148,11 @@ pub trait Copy {
     // Empty.
 }
 
-/// Types that can be safely shared between tasks when aliased.
+/// Types that can be safely shared between threads when aliased.
 ///
 /// The precise definition is: a type `T` is `Sync` if `&T` is
 /// thread-safe. In other words, there is no possibility of data races
-/// when passing `&T` references between tasks.
+/// when passing `&T` references between threads.
 ///
 /// As one would expect, primitive types like `u8` and `f64` are all
 /// `Sync`, and so are simple aggregate types containing them (like