The definite article “the” is used both for singular and plural and all genders. As a general rule the definite article in English is used before a noun that has been mentioned a second time; before a singular noun representing a class of animals or things or a class of people.

It is also used before superlatives¬† such as “the first”, “the second”, etc… and “only” and before a few proper nouns of countries, seas, rivers and so on.

Rule Examples
– Before a noun that has been mentioned a second time I left a book on my desk. Has anybody seen the book I left?
– Before a singular noun representing a class of animals, things or a class of people Today the young have no respect for the old.

The turtle is a protected species.

– Before superlatives and “only” The first person a met yesterday was a beggar.

The only person I trust is my wife.

– Before a few proper nouns of countries, seas, rivers, mountains, and so on. The Alps divide northern Italy from France, Switzerland and Austria.

Tha Sahara desert is the biggest hot desert in the world.

Use of definite article