1. Noun: Also cuestick. A cuestick (or simply cue, more specifically pool cue, snookercue, or billiardscue), is an item of sporting equipment essential to the games of pool, snooker and carombilliards. It is used to strike a ball, usually the cue ball. Cues are tapered sticks, typically about 58 inches (1.5 m) long and 18–21 ounces (510–600 g) for pool (shorter for carom and longer for snooker, and lighter for both). Most cues are made of wood, but occasionally the wood is covered or bonded with other materials including, graphite, carbon fiber or fiberglass. An obsolete term for a cue, used from the 16th to early 19th centuries, is billiardstick.
2. Noun: Sometimes "cue" is short for cue ball.
3. Verb: Same as stroke, definition 1