From WordNet (r) 2.0 (August 2003) [wn]:
1
adj : used of a single unit or thing; not two or more; "`ane' is
Scottish" [syn: one, i, ane]
n : the smallest whole number or a numeral representing this
number; "he has the one but will need a two and three to
go with it"; "they had lunch at one" [syn: one, I,
ace, single, unity]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
1 \1\ adj.
1. used of a single unit or thing; not two or more; --
representing the number one as an Arabic numeral.
Syn: one, i, ane
[WordNet 1.5 +PJC]