an

an — determiner

1. the form of the indefinite article 'a' that you use directly in front of a word

1.determinerA1
Definition

the form of the indefinite article 'a' that you use directly in front of a word whose first sound is a vowel — like the 'a' in 'apple' or the 'o' in 'orange'. The choice depends on the sound, not the spelling, so silent letters and special pronunciations matter.

Example

Bram ate an apple and a banana for breakfast on Tuesday morning.

an + vowel-sound noun (apple); contrast with 'a banana'

Anaya waited for an hour outside the dentist's office in Taipei.

an + silent 'h' (hour starts with vowel sound)

Common collocations
  • an apple
  • an hour
  • an honest answer
  • an old man
  • an engineer
  • an idea
  • an umbrella
  • an X-ray
Antonyms
  • a

    used before words that begin with a consonant sound; the two forms together cover all indefinite-article uses

Grammar Patterns

an + [word starting with vowel sound]

Usage Note

Choice between 'a' and 'an' is decided by the SOUND that follows, never by the spelled letter. Words starting with a silent 'h' (hour, honest, honour, heir) take 'an'. Words spelled with a vowel letter but pronounced with a /j/ or /w/ consonant sound (university, European, one-way, useful) take 'a'.

Common Mistakes

I waited for a hour.
I waited for an hour.
'hour' begins with a vowel sound because the 'h' is silent.
She is studying at an university.
She is studying at a university.
'university' starts with a /j/ sound (like 'you'), which is a consonant sound.
My neighbour is an European tourist.
My neighbour is a European tourist.
'European' begins with a /j/ sound, so use 'a'.
He gave me a honest answer.
He gave me an honest answer.
silent 'h' means the word starts with a vowel sound.

an — suffix

Word family

  • a
    determinerA1
  • one
    numberA1
  • the
    determinerA1

Synonym discussion

Sense: determiner/1

'A' and 'an' are two forms of the same indefinite article — they introduce a noun that the listener has not heard about yet. The choice between them depends only on the sound that follows: 'a' before any consonant sound (a book, a university, a one-way street), and 'an' before any vowel sound (an apple, an hour, an honest mistake). 'The' is the definite article and points to something specific that both speaker and listener already know about. Compare: 'I saw a dog' (any dog, first time mentioned) vs 'I saw an old dog' (still indefinite, but the next word starts with a vowel sound) vs 'I saw the dog' (the particular dog we both know about).

aan ↗the ↗

Common collocations

Nouns

  • an apple
  • an hour
  • an idea
  • an answer
  • an umbrella
  • an honest person
  • an engineer
  • an X-ray

Phrases

  • once an hour
  • an honest mistake
  • an old friend
  • an American citizen

Etymology

Proto-GermanicOld EnglishMiddle EnglishEnglish

'An' is the older form of the indefinite article in English, going back to Old English 'ān' meaning 'one'. In early English, 'an' appeared before every noun. Over time, when the next word started with a consonant sound, the 'n' wore away in casual speech, leaving the shorter form 'a'. The two forms split by the 1300s, and modern usage simply keeps 'n' wherever a vowel sound makes the word easier to say. The same Old English 'ān' is also the source of the number word 'one'.