I present to you, the reader, the definition of the word "the", as taken from dictionary.com:
1.
a. Used before singular or plural nouns and noun phrases that denote particular, specified persons or things: the baby; the dress I wore.
b. 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.
c. Used to indicate uniqueness: the Prince of Wales; the moon.
d. Used before nouns that designate natural phenomena or points of the compass: the weather; a wind from the south.
e. 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.
f. Used before a noun specifying a field of endeavor: the law; the film industry; the stage.
g. Used before a proper name, as of a monument or ship: the Alamo; the Titanic.
h. 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.
2. Used before a singular noun indicating that the noun is generic: The wolf is an endangered species.
3.
a. Used before an adjective extending it to signify a class and giving it the function of a noun: the rich; the dead; the homeless.
b. Used before an absolute adjective: the best we can offer.
4. Used before a present participle, signifying the action in the abstract: the weaving of rugs.
5. Used before a noun with the force of per: cherries at $1.50 the box.
Now I ask you this: Would anybody who didn't understand the meaning of "the" be able to understand what a "noun", "proper name", "adjective", or "participle" is?
Furthermore, the golden rule in defining words is to never use the word itself in the definition. Yet, I see "the" occuring several times in this definition. I'd hate to see them try to define the letter "e" without using it in the definition.