The form of a used before words beginning with a vowel or with an unpronounced h: an elephant; an hour. See Usage Notes at a2, every.(indefinite-article)
Archaic And if; if.(conjunction)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "an" in a sentence
"Security is an exception..an additional cost..a headwind that slows growth."
"But kitteh, it iz krunchee an full uv vitimins an nootrishun an guud fer u an..an…o neber mynd, heer, haz sum toona"
"In an interview, he laughed and described the presidents remarks as an enthusiastic endorsement."