A cock is a rooster, but it's also the hammer on a gun that you adjust so you can fire it. You might hear the word cock used to mean "penis," but that's a vulgar form of the word, so be sure you're in the right company if you opt to use it.
A cock is a male bird, particularly a rooster.
Emphasis on male!
Cock is most often used to refer to either birds or guns. A cock is a rooster, but it's also the hammer on a gun that you adjust so you can fire it.
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