* Noun: When referring to the highest point of something, like a wave or a mountain.
* Example: "The crest of the wave crashed against the shore."
* Verb: To reach the highest point or peak.
* Example: "The stock market crested at a record high."
* Adjective: Describing something that is at the highest point or peak.
* Example: "The cresting wave was a sight to behold."
To determine the correct part of speech, you need to look at how the word is used in context.