* Noun: This is the most common usage. It refers to the organs of sight. Example: "Her eyes were bright blue."
* Verb: It can be a verb meaning "to look at someone or something" or "to follow someone or something with the eyes". Example: "He eyes the menu cautiously."
* Adjective: In some cases, it can be an adjective meaning "related to the eyes". Example: "She has eyeshadow on."
So, the answer is: it depends on the context!