Fist

hand with the fingers curled into the palm

A fist is the the term given to the hand when the four fingers are clenched, and the thumb closed over the first finger. In this solid form, it can be used for striking in combat. The half-closed fist may be used for some tasks, like knocking.

A raised, closed fist

Making a fist is virtually unknown amongst other primates. Their fingers have different proportions to humans.