“The” is used to denote a specific entity

the1     P    (th before a vowel; th before a consonant) def.art. Used before singular or plural nouns and noun phrases that denote particular, specified persons or things: the baby; the dress I wore. Used before a noun, and generally stressed, to emphasize one of a group or type as the most outstanding or prominent: considered Lake Shore Drive to be the neighborhood to live in these days. Used to indicate uniqueness: the Prince of Wales; the moon. Used before nouns that designate natural phenomena or points of the compass: the weather; a wind from the south. Used as the equivalent of a possessive adjective before names of some parts of the body: grab him by the neck; an infection of the hand. Used before a noun specifying a field of endeavor: the law; the film industry; the stage. Used before a proper name, as of a monument or ship: the Alamo; the Titanic. Used before the plural form of a numeral denoting a specific decade of a century or of a life span: rural life in the Thirties.