What is the meaning of Billiard?

A shot in billiards or snooker in which the cue ball strikes two other balls; a carom.

Pertaining to the game of billiards.

A dynamical system in which a particle alternates between motion in a straight line and specular reflections from a boundary.

10, a thousand billion (long scale) or a million milliard.

quadrillion (10)

Source: wiktionary.org