Is an oxymoron a part of speech?

Here's why:

* Parts of speech describe the grammatical function of words (like noun, verb, adjective, etc.).

* An oxymoron is a figure of speech that combines contradictory terms (e.g., "deafening silence," "living dead").

So, while an oxymoron uses words, it's not a word category itself. It's a specific way of using words for a particular effect.