What part of speech is "park" in the sentence: "They went to the park"?

The word "park" in the sentence "They went to the park" functions as a noun. Nouns are words that represent people, places, things, or ideas. In this instance, "park" refers to a specific place where people can visit, thus demonstrating its role as a noun. It identifies the location to which "they" went, helping convey the meaning of the sentence.

In contrast, the other parts of speech listed in the choices do not apply here. Adjectives describe or modify nouns, but "park" does not serve that purpose in this context. A verb denotes an action or state of being, and while "went" is the action in this sentence, "park" does not represent an action. Lastly, adverbs typically modify verbs, adjectives, or other adverbs to provide more information about how, when, where, or to what extent something happens, which is also not the case for "park" in this sentence.