A numerical value equal to 9; the number following eight and preceding ten.

Describing a group or set with nine elements.

The digit or figure 9.

(card games) A playing card with nine pips.

(weaponry) A nine-millimeter semi-automatic pistol.

(computing, engineering, usually in the plural) A statistical unit of proportion (of reliability, purity, etc.).

(baseball) A baseball club, team, or lineup (composed of nine players).