What part of speech is the word hundred?

The word "hundred" can be a few different parts of speech depending on how it's used:

* Adjective: When it describes a noun, like "a hundred dollars".

* Noun: When it refers to the number itself, like "hundreds of people".

* Numeral: When it acts as a number, like "one hundred".

So, to determine the part of speech, look at how it's being used in the sentence.