Definite and Indefinite article

We use indefinite article to talk about something in particular. In this case, we use the.

Ex: The car in the parking lot is red

We use definite article, when we are talking about something in general. In this case, we use a or an.

If the following word starts with a consonant sound, then we say a:

Ex: a cat, a door, a game

If the following word starts with a vowel sound, then we an:

Ex: an elefant, an ice-cream, an umbrella