What part of speech is the word ha?

"Ha" can be a few different parts of speech, depending on the context:

* Interjection: This is the most common use of "ha." It expresses amusement, surprise, or triumph.

* Example: "Ha! You fell for it!"

* Noun: Used to refer to the sound itself.

* Example: "The comedian's 'ha' was infectious."

* Verb: Can be used to describe the act of laughing.

* Example: "He ha-ed at the joke."

Without more context, it's difficult to determine the exact part of speech.