1. how much there is or how many there are of something that you can quantify
2. an adequate or large amount
he had a quantity of ammunition
3. the concept that something has a magnitude and can be represented in mathematical expressions by a constant or a variable
4. The attribute of being so much, and not more or less; the property of being measurable, or capable of increase and decrease, multiplication and division; greatness; and more concretely, that which answers the question "How much?"; measure in regard to bulk or amount; determinate or comparative dimensions; measure; amount; bulk; extent; size.