Is the word the a preposition?

Answer 1

No, "the" is an article, a special form of determiner used like an adjective, to indicate a specific member of a group or set.

Of, under, with, against, through, up, down, without, etc. are examples of prepositions.

Answer 2

No, the word "the" is not a preposition. "The" is a definite article that is used to specify a noun.