From The Demon's Dictionary, by Ambrose Bierce:

A.

The first letter in every properly constructed alphabet. It is the first natural utterance of the human vocal organs, and is variously sounded, according to the pleasure and convenience of the speaker. In logic, A asserts and B denies. Assertions being proverbially untrue, the presumption would be in favor of B’s innocence were it not that denials are notoriously false. In grammar, A is called the indefinite article, probably because, denoting a definite number, it is so obviously a numeral adjective.



NOTE: The Demon's Dictionary was published by Bierce in the December 11, 1875 edition of the San Francisco News Letter. The Demon’s Dictionary was later incorporated into The Devil’s Dictionary in 1967 by Ernest J. Hopkins, thus creating The Enlarged Devil’s Dictionary, which, naturally, remains copyrighted.