Determiners come before nouns and tell us something about their number, definiteness, proximity, and ownership.
Definite article – the
The American Heritage Dictionary of the English Language
The definite article, functioning as an adjective. It is used: 1. Before singular or plural nouns and noun phrases that denote particular specified persons or things. 2. Before a singular noun, making it generic: the human arm. 3. Before a noun, and generally stressed, emphasizing its uniqueness or prominence: That’s THE show to see this year. 4. Before a title of rank or office, designating its holder: The President arrives tomorrow. 5. Before an adjective, extending it to signify a class and giving it the function of a noun: the rich; the beautiful. 6. Before an adjective used absolutely: the finest we have to offer. 7. Before a present participle, signifying the action in the abstract: the weaving of rugs. 8. Before a noun, with the force of per: at a dollar the box.