What part of speech is the word surface?

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

* Noun: When it refers to the outer layer of something.

* Example: "The surface of the water was calm."

* Verb: When it means to come to the surface or to appear on the surface.

* Example: "The submarine surfaced near the island."

* Adjective: When it describes something as being on the surface or superficial.

* Example: "They only had a surface understanding of the problem."

Therefore, you need to consider the context of the sentence to determine the specific part of speech for "surface".