A (2)

A (ȧ emph. ā). 1. 1. [[Shortened form of an. AS. ān one. See One.]] An adjective, commonly called the indefinite article, and signifying one or any, but less emphatically. “At a birth”; “In a word”; “At a blow”. Shak. It is placed before nouns of the singular number denoting an individual object, or a quality individualized, before collective nouns, and also before plural nouns when the adjective few or the phrase great many or good many is interposed; as, a dog, a house, a man; a color; a sweetness; a hundred, a fleet, a regiment; a few persons, a great many days. It is used for an, for the sake of euphony, before words beginning with a consonant sound [for exception of certain words beginning with h, see An]; as, a table, a woman, a year, a unit, a eulogy, a ewe, a oneness, such a one, etc. Formally an was used both before vowels and consonants.
2. 2. [[Originally the preposition a (an, on).]] In each; to or for each; as, “twenty leagues a day”, “a hundred pounds a year”, “a dollar a yard”, etc.