aW1S1 [ə strong eı] indefinite article, determiner also an1.) used to show that you are talking about someone or something that has not been mentioned before, or that your listener does not know about▪ We have a problem.▪ There was a hole in the fence.▪ Suddenly they heard a loud bang.→↑the12.) used to show that you are referring to a general type of person or thing and not a specific person or thing▪ Would you like a sandwich?▪ I want to train to be an engineer.▪ He's a really nice man.▪ Take a look at this.▪ It needs a good clean.3.) used before someone's family name to show that they belong to that family▪ One of his daughters had married a Rothschild.4.) one▪ a thousand pounds▪ a dozen eggs▪ You'll have to wait an hour or two.5.) used in some phrases that say how much of something there is▪ There were a lot of people at the party.▪ A few weeks from now I'll be in Venice.▪ You have caused a great deal of trouble.6.) used to mean 'each' when stating prices, rates, or speeds▪ I get paid once a month.▪ The eggs cost $2 a dozen.7.) used before singular nouns to mean all things of a particular type▪ A square has four sides (=all squares have four sides) .▪ A child needs love and affection.8.) used once before two nouns that are mentioned together very often▪ I'll fetch you a cup and saucer.▪ Does everyone have a knife and fork?9.) used before the -ing forms of verbs when they are used as nouns referring to an action, event, or sound▪ There was a beating of wings overhead.▪ Bernice became aware of a humming that seemed to come from all around her.10.)used before nouns that are usually ↑uncountable when other information about the quality, feeling etc is added by an adjective, phrase, or ↑clause▪ Candidates must have a good knowledge of chemistry.11.) used before the name of a substance, food etc to refer to a particular type of it▪ Use a good cheese to make the sauce.▪ plants that grow well in a rich moist soil12.) used before the name of a drink to refer to a cup or glass of that drink▪ Can I get you a coffee?▪ Renwick went to the bar and ordered a beer.13.) used before the name of a famous artist to refer to a painting by that artist▪ an early Rembrandt14.) used before a name to mean someone or something that has the same qualities as that person or thing▪ She was hailed as a new Marilyn Monroe.15.) used before someone's name when you do not know who they are▪ There is a Mr Tom Wilkins on the phone.16.) used before the names of days, months, seasons, and events in the year to refer to a particular one▪ We arrived in England on a cold wet Sunday in 1963.▪ I can't remember a Christmas like it.▬▬▬▬▬▬▬WORD CHOICE: a, anBefore a word beginning with a vowel sound, use an : an elephant | an umbrella | an obvious mistake!! Use an before an 'h' that is not pronounced : an hour later |an honest explanation!! Use a before a 'u' that is pronounced like 'you' : a university | a unique opportunity!! Use an before an abbreviation that is pronounced with a vowel sound at the start : an SOS call |an MP3 file▬▬▬▬▬▬▬
Dictionary of contemporary English. 2013.