A small ornament suspended from a watch chain, e.g. a fob seal.The word 'fob' originally referred to a small pocket, particularly a small pocket in a man's trousers just below the waistband, in which a pocket watch was carried; but when it became the custom to awear a watch on a chain, the word became associated with the chain (i.e. 'fob chain') and later it designated an ornament suspended from the chain.Also used for a ribbon, mesh band or similar article attached to the 'bow' (ring) of a watch when it is carried in the watch pocket, hanging from the pocket and having some decorative ornament orfob seal attached to it.
Fob

Fob
A small ornament suspended from a watch chain, e.g. a fob seal.The word 'fob' originally referred to a small pocket, particularly a small pocket in a man's trousers just below the waistband, in which a pocket watch was carried; but when it became the custom to awear a watch on a chain, the word became associated with the chain (i.e. 'fob chain') and later it designated an ornament suspended from the chain.Also used for a ribbon, mesh band or similar article attached to the 'bow' (ring) of a watch when it is carried in the watch pocket, hanging from the pocket and having some decorative ornament orfob seal attached to it.
References
From: An Illustrated Dictionary of Jewelry, autor: Harold Newman, publishers: Thames and Hudson



