the concept that something has a magnitude and can be represented in mathematical expressions by a constant or a variable
"The physicist adjusted the equation to treat mass as a quantity, allowing it to function either as a fixed constant or a shifting variable depending on the scenario."
A fundamental, generic term used when referring to the measurement (count, amount) of a scalar, vector, number of items or to some other way of denominating the value of a collection or group of items.
"When calculating the total mass of the shipment, the quantity remains constant regardless of how we choose to measure it in kilograms or pounds."
In plain English: Quantity is the total amount of something you have or use.
"The quantity of sugar needed for this recipe is surprisingly small."
Usage: Use quantity to refer to an unspecified large amount rather than specific numbers. It is often confused with quality, which describes characteristics instead of measurable amounts.
The word quantity entered English from the Old French quantité and originally meant "how much." It traveled directly into our language with this same sense of amount or number.