What part of speech is hundreds?

"Hundreds" can be a few different parts of speech depending on its use in a sentence:

* Noun: When referring to a large, unspecified quantity.

* Example: "There were hundreds of people at the concert."

* Adjective: When describing a quantity of something.

* Example: "She bought hundreds of books."

* Determiner: When specifying a quantity of something.

* Example: "Hundreds of students protested."

Let me know the sentence you're considering, and I can tell you the specific part of speech for "hundreds" in that context.