Definition of an:

part of speech: conjunction

Noting a single individual, but less emphatic than one; the indefinite article, put before nouns or adjs. in the sing. beginning with a vowel or the sound of a vowel- as, an egg, an honourable man.

Usage examples:

• It was an all- day matter. in "".

• The lady saw an opening and went in. Alexander Irvine in "My Lady of the Chimney Corner".

• The Hebrews had been feared when he was an infant. G. A. Chadwick in "The Expositor's Bible: The Book of Exodus".

• You'll be an artist? Payne Erskine in "The Eye of Dread".