* Noun: A sequence of musical notes, often a melody.
* *The pianist played a beautiful tune.*
* Verb: To adjust something to a desired state, often referring to musical instruments.
* *She tuned her violin before the concert.*
* Adjective: In some cases, it can be used as an adjective meaning "in good working order".
* *The engine is tune.* (Though this usage is less common)
Let me know if you have a specific sentence in mind, and I can help you determine the part of speech of "tune" in that context.