Fob and Keychain

Fob noun - Short chain or ribbon attaching a pocket watch to a man's vest.

Keychain and fob are semantically related in charm topic. In some cases you can use "Keychain" instead a noun "Fob", when it comes to topics like pendant, keyring.

Fob and keychain are semantically related in charm topic. You can use "Fob" instead a noun "Keychain", if it concerns topics such as pendant, keyring.