What does an mean?
'An' is the indefinite article of English, used before singular nouns that begin with a vowel sound to refer to one unspecified member of a class: an apple, an idea, an hour. It is identical in meaning to 'a'; the two forms are variants of a single ancient word, with 'an' surviving where the following vowel sound makes the extra 'n' easier to pronounce. The choice is governed by sound rather than spelling, so we say 'an hour' but 'a university.' Beyond its core use, 'an' appears in rate expressions such as 'twice an hour,' standing in for 'per.' Though among the smallest and most frequently used words in the language, it carries a remarkable history: it descends directly from Old English 'ān,' meaning 'one,' making it a living fossil of the language's earliest vocabulary.
The indefinite article placed before a singular noun beginning with a vowel sound, indicating one unspecified instance of that noun.
"An owl hooted somewhere in the garden."
Use 'an' before vowel sounds ('an egg') and 'a' before consonant sounds ('a book'), regardless of spelling.
In fixed expressions of rate, functions like 'per': 'twice an hour' means twice per hour.
"The medication is taken three times a day, roughly every eight hours."
Before the 1400s there was no separate word 'a' — 'an' was the only form, and 'a' is simply 'an' with its n worn away by centuries of fast speech.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of an
'An' descends from Old English 'ān,' meaning 'one,' which also gave rise to the modern word 'one.' In Middle English the numeral weakened into an indefinite article, and by the fourteenth century the reduced form 'a' had split off from 'an' through the loss of the final 'n' in rapid speech. It shares this ancient root with cognates across the Germanic family, such as German 'ein' and Dutch 'een,' and more distantly with Latin 'ūnus,' source of words like 'union' and 'unique.'
Related word forms
How an is actually used
The choice between 'a' and 'an' depends on sound, not spelling: 'an hour' but 'a university,' because 'hour' begins with a vowel sound while 'university' begins with /j/. 'An' is unstressed in ordinary speech and takes its full form /æn/ only under emphasis.
Easily confused with an
'An' is the indefinite article meaning 'one of many,' while 'and' is a conjunction joining words or phrases together.