The wordan is used before vowel sounds, anda before consonant sounds:

a dog

an egg

an hour (theh is not pronounced)

a hog (theh is pronounced)

a yak (y is a consonant sound in this word)

anyngling (y represents a vowel sound)

a/an user (has consonant /j/ or vowel /ɪu/ as its initial sound)

a/an username

an umbrella (has vowel /ʌ/ as its initial sound, which is a vowel)

a woman (/w/ is a consonant)

a one (has consonant /w/ as its initial sound)

an onion (has vowel /ʌ/ as its initial sound)

• There is one occasional exception. The forman is sometimes used beforeh when the first syllable is not accented because it is sometimes dropped. The usual example isan historic occasion. Though current in some dialects that pronounce theh, this is considered by many to be affected, pedantic or obsolete.

Some words, such asone,user anduniversity, begin with vowel letters but consonant sounds. These are preceded bya, notan. Historically, many of these words could be preceded byan, but this is because they used to begin with vowel sounds; soan can still be said to occur only before vowel sounds.

The wordthe is used as the definite article for both singular and plural nouns, and before vowel sound and consonant sounds alike. However, for many English speakers, the pronunciation is /ðə/ before a consonant sound and /ðɪ/ before a vowel sound; this distinction is not indicated in writing. The pronunciation /ði/ is also used for emphasis; this is indicated in writing by italics, as in “the best” (followed by a noun).

Certain loanwords contain articles from foreign languages, for examplea la,hoi polloi, andalcohol.

• TheWikipedia article about articles.

• English articles
• English grammar appendices