metal cap; ferrule
A metal fitting that caps or reinforces the end of an object, such as a walking stick, umbrella tip, or brush handle.
この杖の口金が外れてしまった。
The metal cap on this walking stick has come off.
A metal clasp or fastener, often found on bags, purses, or cases.
がま口の口金が壊れて、財布が閉まらない。
The clasp on the coin purse broke, and the wallet won't close.
The mouthpiece of a wind instrument or a similar part that contacts the mouth.
トランペットの口金を消毒してください。
Please disinfect the trumpet mouthpiece.
socket; light socket
A socket for a light bulb or similar electrical component.
電球を口金にしっかり差し込んでください。
Please insert the light bulb firmly into the socket.
Compound of 口 (kuchi, 'mouth, opening') and 金 (kane, 'metal'), referring to a metal fitting at an opening. The exact historical derivation is uncertain.