What part of speech is the word pay?

The word "pay" can be several parts of speech depending on how it's used in a sentence:

* Verb: This is the most common usage. Example: "I will pay you tomorrow."

* Noun: This refers to the money used for payment. Example: "I received my pay today."

* Adjective: This is less common and describes something related to payment. Example: "The pay phone is out of order."

Let me know if you have a sentence in mind, and I can tell you which part of speech "pay" is functioning as in that specific case!