Definition of "twelve"

The cardinal number occurring after eleven and before thirteen, represented in Arabic numerals as 12 and in Roman numerals as XII.  examples

A group of twelve items.  examples

A twelve-bore gun.  quotations  examples

(law, colloquial) A jury (normally composed of twelve persons).  examples

(slang) The police; law enforcement, especially a narcotics officer.

(military slang, by ellipsis of twelve o'clock) Front (front side of something, position in front of something).