From WordNet (r) 2.0 (August 2003) [wn]:
12
adj : denoting a quantity consisting of 12 items or units [syn:
twelve, xii, dozen]
n : the cardinal number that is the sum of eleven and one [syn:
twelve, XII, dozen]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
12 \12\ adj.
1. denoting a quantity consisting of 12 items or units; --
representing the number twelve as Arabic numerals
Syn: twelve, xii, dozen
[WordNet 1.5 +PJC]