What part of speech is glass?

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

* Noun: This is the most common usage. "The glass shattered on the floor."

* Adjective: "She wore a glass necklace."

* Verb: This is less common, but it's used to describe the process of making something glassy. "The potter glassed the surface of the bowl."

To determine the part of speech, you need to look at the context of the sentence.