What Is the String Worn Around the Neck That Holds Keys Called?

A lanyard is the string worn around the neck to hold keys. It can also hold USB devices, identification, a whistle, a tool or knife, a pen or anything else that has a loop or clip through which a lanyard can be fastened.

Lanyards are usually made of a cloth that can lay flat against the chest and neck and have a metal fastener at one end. Those that hold keys typically have a thin clip that can be threaded through a key chain or a hole in the key itself, and they may slide over the head or have a fastener that latches behind the neck.