From The Collaborative International Dictionary of English v.0.48 [gcide]:
An \An\, conj. [Shortened fr. and, OE. an., and, sometimes and
if, in introducing conditional clauses, like Icel. enda if,
the same word as and. Prob. and was originally pleonastic
before the conditional clause.]
If; -- a word used by old English authors. --Shak.
[1913 Webster]
Nay, an thou dalliest, then I am thy foe. --B. Jonson.
[1913 Webster]
An if, and if; if.
[1913 Webster]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
An \An\ ([a^]n). [AS. [=a]n one, the same word as the numeral.
See One, and cf. A.]
This word is properly an adjective, but is commonly called
the indefinite article. It is used before nouns of the
singular number only, and signifies one, or any, but somewhat
less emphatically. In such expressions as "twice an hour,"
"once an age," a shilling an ounce (see 2d A, 2), it has a
distributive force, and is equivalent to each, every.
[1913 Webster]
Note: An is used before a word beginning with a vowel sound;
as, an enemy, an hour. It in also often used before h
sounded, when the accent of the word falls on the
second syllable; as, an historian, an hyena, an heroic
deed. Many writers use a before h in such positions.
Anciently an was used before consonants as well as
vowels.
[1913 Webster]
From WordNet (r) 3.0 (2006) [wn]:
AN
n 1: an associate degree in nursing [syn: {Associate in
Nursing}, AN]
From The Free On-line Dictionary of Computing (8 July 2008) [foldoc]:
an
<networking> The country code for the Netherlands Antilles
(Dutch Antilles).
(1999-01-27)