What part of speech is the word duplicate?

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

* Verb: To make an exact copy of something. ("Please duplicate this file.")

* Noun: An exact copy. ("This painting is a duplicate of the original.")

* Adjective: Being an exact copy. ("He gave me a duplicate key.")

So, to determine the part of speech, you need to look at the context in which the word is used.