An

From Old English Än.

1898, Winston Churchill, The Celebrity Chapter 2, Sunning himself on the board steps, I saw for the first time Mr. Farquhar Fenelon Cooke. He was dressed out in broad gaiters and bright tweeds, like an English tourist, and his face might have belonged to Dagon, idol of the Philistines.

(UK, non-standard) Form of Form used in many British regional accents before some words beginning with a pronounced h

The article an is used before vowel sounds and (optionally) before silent aitches, and a before consonant sounds.

The various article senses of a, all are senses of an.

From Middle English an

Full definition of an

(archaic) If, so long as.An it please you, my lord.
(archaic) as if; as though.Samuel Taylor Coleridge, The Rime of the Ancyent Marinere (Original Version of 1797) 61-64:At length did cross an Albatross, Thorough the Fog it came; And an it were a Christian Soul, We hail'd it in God's Name.

Borrowing from ka {{2}}.

(plural ans)

From the Old English preposition an/on.

This is the same as the word a in such contexts, modified because of preceding an unpronounced h. The train was speeding along at a mile a minute.