A

The first letter in the Roman alphabet, derived from the Greek letter alpha which is pretty much the same in shape and function. Like other Latin vowels, a came in a long (sounded as in father) and a short (sounded as in Dinah) variety. In other languages which use the letter it takes on various other values, notably in English the sound in cat, formerly represented by an a-e ligature called æsc.

On computers the uppercase letter is represented with ASCII code 65 and the lowercase letter with code 97.