Learn more about Grammar:
Adjectives: An Easy Guide with ExamplesAdverbial Clauses: What Are They?AdverbsAnalogy: Definition & Meaning (with Examples)ArticlesBad AdverbsClauses: Definition, Meaning, and How to Use ThemConjunctionsCoordinating Conjunctions: What Are They and When Should You Use Them?Dangling ModifiersDeclarative Sentence: Examples + MeaningExaggerationHomophones: Definition and ExamplesHow to Use Subordinating ConjunctionsInfinitivesInterjections: Definition, Meaning, and ExamplesIntransitive Verb: Definition, Meaning, and ExamplesNounsParticiples PluralsPrepositional Phrase: What Is It & How to UsePrepositionsSplit Infinitive: The Complete Guide (with Examples)Subordinate Clause: Definition, Types, and ExamplesThe Complete Guide to Transitive VerbsTransitions: A Complete Guide (with 100+ Examples)Types of VerbsVerbs: Types of Verbs, Definition and ExamplesWhat is a Pronoun? Rules and ExamplesWhat Is Symbolism in Writing?Word ClassesShould I use "a" before plural nouns?

A and an are indefinite articles that are used to identify nouns. They are non-specific and can refer to any member of a group.
Here are some examples:
- My sister is buying a car.
- My brother went out to buy an apple.
A and an can only be used with singular nouns. You shouldn't use them with plural nouns.
If you are using a plural noun, you will either need to change the article to 'the' or specify the number of items:
- I bought the magazines.
- I bought two magazines.