A guy straining his biceps brachii.

Biceps is a Latin term that means two heads. It describes muscles that are made up of two distinct parts.

In general usage, biceps usually refers to biceps brachii. The biceps brachii is the prominent muscle on the upper arm, and are associated with strength.

Biceps can also refer to the biceps femoris, one of the hamstring muscles of the underside of the thigh.