diff --git a/lib/std/heap/arena_allocator.zig b/lib/std/heap/arena_allocator.zig
index 15d9044479..f88bb7de16 100644
--- a/lib/std/heap/arena_allocator.zig
+++ b/lib/std/heap/arena_allocator.zig
@@ -3,8 +3,10 @@ const assert = std.debug.assert;
 const mem = std.mem;
 const Allocator = std.mem.Allocator;
 
-/// This allocator takes an existing allocator, wraps it, and provides an interface
-/// where you can allocate without freeing, and then free it all together.
+/// This allocator takes an existing allocator, wraps it, and provides an interface where
+/// you can allocate and then free it all together. Calls to free an individual item only
+/// free the item if it was the most recent allocation, otherwise calls to free do
+/// nothing.
 pub const ArenaAllocator = struct {
     child_allocator: Allocator,
     state: State,