What part of speech is the word traffic?

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

* Noun: This is the most common use. It refers to the movement of vehicles, people, or information.

* Example: "The traffic was heavy on the highway."

* Verb: This is less common, but it means to deal with or exchange information or goods.

* Example: "The company trafficked in illegal drugs."

* Adjective: This is also less common, but it describes something related to traffic.

* Example: "They had a traffic problem on the road."

So, the part of speech depends on the context of the sentence.