fob

Fob is a term with several related but distinct meanings in English. In modern usage it most commonly refers to two objects: a key fob, a small device used to unlock or start a vehicle or to gain access to facilities, and a fob watch accessory, a decorative or functional pendant attached to a pocket watch by a chain.

A key fob often contains a microchip and, in some cases, a battery. It works with a vehicle’s or building’s security system through radio frequency identification (RFID), near-field communication (NFC), or Bluetooth technology. Proximity sensing enables features such as keyless entry, remote unlocking, or even remote start. Some systems also support digital keys that reside on smartphones in addition to or instead of a physical fob. Historically, key fobs are tied to the rise of remote access controls and have become common in cars, offices, and secure facilities.

The watch fob refers to a chain, ribbon, or tassel used to secure a pocket watch to clothing and sometimes to help draw the watch from a pocket. The term also designates the small pocket on a waistcoat or the chain that connects the watch to the wearer. In contemporary contexts, fobs may be purely decorative or fashioned as jewelry, while still serving as a link to a pocket watch heritage.

The verb phrase to fob off means to pass something unwanted off as acceptable or to mislead or persuade someone to accept a lesser or different item. The origin of fob in the senses related to pockets and watches dates to the 17th century, and the precise etymology is uncertain.