1. A male bird, especially of a domestic fowl/rooster.
2. A slang for penis/dick.
3. Male of other animals: While most commonly referring to birds, it can also refer to the male of certain other animals, like a cock lobster.
4. Verb "to cock": This can mean to draw back the hammer of a gun in preparation for firing, or to tilt or turn something upwards or to one side, such as cocking one's head.
5. A small pile: As a noun, it can refer to a small heap of hay or straw.