What part of speech is dollar?

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

* Noun: This is the most common usage, referring to the unit of currency. Example: "I have five dollars."

* Adjective: It can describe something related to money or the U.S. currency. Example: "That's a dollar bill."

* Verb: Less common, but can mean "to evaluate something in terms of money." Example: "I'm going to dollar the value of this antique."

So, without context, it's hard to say for sure.