What part of speech is a lot?

"A lot" can be a few different parts of speech, depending on how it's used:

* Adjective: When used to describe a quantity, like "There were a lot of people at the party."

* Adverb: When used to modify a verb, adjective, or other adverb, like "I like that shirt a lot."

* Pronoun: In informal speech, "a lot" can act as a pronoun meaning "many" or "much", like "We didn't have a lot of time."

It's important to consider the context to determine its specific part of speech.