What part of speech is the word check?

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

Verb:

* "Please check your email."

Noun:

* "Write a check for $50."

* "The doctor gave her a checkup."

Adjective:

* "Do you have a check engine light on?"

Interjection:

* "Check it out!"

So, to determine the part of speech, you need to look at its context within the sentence.