* Noun: When referring to an original model or first example of something, "prototype" is a noun.
* Example: "The engineer built a prototype of the new car."
* Adjective: When used to describe something as being an original or initial model, "prototype" is an adjective.
* Example: "This is a prototype design, so it might change."
* Verb: Though less common, "prototype" can be used as a verb meaning "to make a prototype of."
* Example: "The team will prototype the new software before releasing it."
So, the part of speech depends on the context!