What part of speech is observer?

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

* Noun: A person who observes something.

* Example: "The observer recorded the data carefully."

* Adjective: Relating to observation.

* Example: "The observer deck offered a clear view of the city."

* Verb: (archaic) To keep watch or observe.

* Example: "The soldiers observed the enemy camp."

Let me know if you have a specific sentence in mind and I can help you determine the part of speech in that context.