Top definition
When a guy and a girl are going out and the girl just hangs all over the guy. The guy doesn't care. The girl is useless and hangs there much like a keychain to a backpack.
girl: (hugs boy)
boy: meh

observing girls: god, that girl is such a keychain
by TangoMaureen December 10, 2005
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2
The visible print made by a man's penis on the front of the pants. The phallic formation seen through a man's trousers, shorts, or jeans. See also DICK PRINT

Plural: keychains
We were too distracted by the keychain at the amusement park to really enjoy the roller coaster.
by q.wsmith March 31, 2010
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3
In the act of threesome with two males and one female. A keychain happens when one male drives his penis in the females vagina, as the other male drives his penis in the females anus all at the same time. In which creates an effect of a keychain.
"Dude we keychained this bitch last night!"
by AccurateDefinitions4578 January 12, 2015
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