A vs. An vs. And

indefinite article used before nouns; often confused with 'an' which is used before a noun that begins with a vowel sound

There is no indefinite article 'a' or 'an' before nouns in Russian.

indefinite article; 'an' is used before a vowel sound. often confused with 'a' which is used before nouns that begin with a consonant.

I think this is an exception.

conjunction; used to connect words; used to show addition

I'll have a black coffee and muffin please.