* Noun: This is the most common usage. It refers to the amount or number of something.
* Example: "The quantity of apples in the basket was impressive."
* Adjective: This is less common but still valid. It describes something as being related to quantity.
* Example: "The quantity discount was a great deal."
* Pronoun: In very specific contexts, "quantity" can function as a pronoun, standing in for a previously mentioned quantity.
* Example: "We need to order a large quantity of paper, and we'll need the same quantity of pens."
It's important to understand the context to determine the correct part of speech for "quantity."