What part of speech is coupon?

"Coupon" can be a few different parts of speech, depending on how it's used in a sentence:

* Noun: This is the most common usage. A coupon is a certificate that entitles the holder to a discount or other benefit.

* Example: "I used a coupon to get 20% off my groceries."

* Verb: While less common, "coupon" can also be a verb meaning "to reduce the cost of something with a coupon".

* Example: "The store is couponing all of its products this week."

So, the part of speech for "coupon" depends on its context in the sentence.