diff --git a/src/lib/es2015.collection.d.ts b/src/lib/es2015.collection.d.ts
index 43129531845e4..84bbe73f7c0af 100644
--- a/src/lib/es2015.collection.d.ts
+++ b/src/lib/es2015.collection.d.ts
@@ -94,7 +94,7 @@ interface Set<T> {
      */
     has(value: T): boolean;
     /**
-     * @returns the number of (unique) elements in Set.
+     * @returns the number of (unique) elements in the Set.
      */
     readonly size: number;
 }