diff --git a/tsc/internal/bundled/libs/lib.es2015.core.d.ts b/tsc/internal/bundled/libs/lib.es2015.core.d.ts
index e36b9fbdadd0c..d3f1eadf81ed7 100644
--- a/tsc/internal/bundled/libs/lib.es2015.core.d.ts
+++ b/tsc/internal/bundled/libs/lib.es2015.core.d.ts
@@ -399,9 +399,10 @@ interface RegExpConstructor {
 
 interface String {
     /**
-     * Returns a nonnegative integer Number less than 1114112 (0x110000) that is the code point
-     * value of the UTF-16 encoded code point starting at the string element at position pos in
-     * the String resulting from converting this object to a String.
+     * Returns a nonnegative integer Number less than 1114112 (0x110000) that is the Unicode
+     * code point value starting at the string element at position pos in the String resulting
+     * from converting this object to a String. Note that this is the code point starting at pos,
+     * not the pos-th code point of the string.
      * If there is no element at that position, the result is undefined.
      * If a valid UTF-16 surrogate pair does not begin at pos, the result is the code unit at pos.
      */
diff --git a/tsc/internal/bundled/libs/lib.es5.d.ts b/tsc/internal/bundled/libs/lib.es5.d.ts
index e394111cb0e6c..4f86ffe9f1ff0 100644
--- a/tsc/internal/bundled/libs/lib.es5.d.ts
+++ b/tsc/internal/bundled/libs/lib.es5.d.ts
@@ -416,8 +416,8 @@ interface String {
     charAt(pos: number): string;
 
     /**
-     * Returns the Unicode value of the character at the specified location, or NaN if the index is out of bounds.
-     * @param index The zero-based index of the desired character.
+     * Returns the UTF-16 code unit at the specified index, or NaN if the index is out of bounds.
+     * @param index The zero-based index of the desired code unit.
      */
     charCodeAt(index: number): number;