In the sentence "Where is the book? It's on (the) table," what part of speech is the word in parentheses?

In the sentence "Where is the book? It's on (the) table," the word in parentheses, "the," functions as a definite article. A definite article is used to refer to specific nouns that are known to the speaker and the listener. In this case, "the table" refers to a particular table that is understood by both the person asking the question and the person answering it.

The use of "the" signals that it is not just any table, but a specific one that is likely already known in the context. This contrasts with an indefinite article, which would introduce a noun that is not specified or known, such as "a" or "an." Understanding this distinction helps clarify why "the" is categorized as a definite article in this sentence.