diff --git a/src/liballoc/arc.rs b/src/liballoc/arc.rs
index 5faf4dcccaf..5ed41f6ffe6 100644
--- a/src/liballoc/arc.rs
+++ b/src/liballoc/arc.rs
@@ -42,7 +42,8 @@
 /// necessarily) at _exactly_ `MAX_REFCOUNT + 1` references.
 const MAX_REFCOUNT: usize = (isize::MAX) as usize;
 
-/// A thread-safe reference-counting pointer.
+/// A thread-safe reference-counting pointer. 'Arc' stands for 'Atomically
+/// Reference Counted'.
 ///
 /// The type `Arc<T>` provides shared ownership of a value of type `T`,
 /// allocated in the heap. Invoking [`clone`][clone] on `Arc` produces
diff --git a/src/liballoc/rc.rs b/src/liballoc/rc.rs
index 33951b911dd..1f3388ad2c2 100644
--- a/src/liballoc/rc.rs
+++ b/src/liballoc/rc.rs
@@ -10,7 +10,8 @@
 
 #![allow(deprecated)]
 
-//! Single-threaded reference-counting pointers.
+//! Single-threaded reference-counting pointers. 'Rc' stands for 'Reference
+//! Counted'.
 //!
 //! The type [`Rc<T>`][`Rc`] provides shared ownership of a value of type `T`,
 //! allocated in the heap. Invoking [`clone`][clone] on [`Rc`] produces a new
@@ -266,7 +267,8 @@ struct RcBox<T: ?Sized> {
     value: T,
 }
 
-/// A single-threaded reference-counting pointer.
+/// A single-threaded reference-counting pointer. 'Rc' stands for 'Reference
+/// Counted'.
 ///
 /// See the [module-level documentation](./index.html) for more details.
 ///