Noun

Singular quantity

Plural quantities

quantity (plural quantities)

1. 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.

   You have to choose between quantity and quality.

2. An indefinite amount of something.

   Some soap making oils are best as base oils, used in a larger quantity in the soap, while other oils are best added in a small quantity.

   Olive oil can be used practically in any quantity.

3. A specific measured amount.

   This bag would normally costs $497.50 for a quantity of 250, at a price of $1.99 per piece.

   Generally it should not be used in a quantity larger than 15 percent.

4. A considerable measure or amount.

   The Boeing P-26A was the first all-metal monoplane fighter produced in quantity for the U.S. Army Air Corps.

5. (mathematics) Indicates that the entire preceding expression is henceforth considered a single object.

   x plus y quantity squared equals x squared plus 2xy plus y squared.

Quantity is a kind of property which exists as magnitude or multitude. It is among the basic classes of things along with quality, substance, change, and relation. Quantity was first introduced as quantum, an entity having quantity. Being a fundamental term, quantity is used to refer to any type of quantitative properties or attributes of things. Some quantities are such by their inner nature (as number), while others are functioning as states (properties, dimensions, attributes) of things such as heavy and light, long and short, broad and narrow, small and great, or much and little. One form of much, muchly is used to say that something is likely to happen. A small quantity is sometimes referred to as a quantulum.

Two basic divisions of quantity, magnitude and multitude, imply the principal distinction between continuity (continuum) and discontinuity.

Under the names of multitude come what is discontinuous and discrete and divisible into indivisibles, all cases of collective nouns: army, fleet, flock, government, company, party, people, chorus, crowd, mess, and number. Under the names of magnitude come what is continuous and unified and divisible into divisibles, all cases of non-collective nouns: the universe, matter, mass, energy, liquid, material, animal, plant, tree.

Along with analyzing its nature and classification, the issues of quantity involve such closely related topics as the relation of magnitudes and multitudes, dimensionality, equality, proportion, the measurements of quantities, the units of measurements, number and numbering systems, the types of numbers and their relations to each other as numerical ratios.

Thus quantity is a property that exists in a range of magnitudes or multitudes. Mass, time, distance, heat, and angular separation are among the familiar examples of quantitative properties. Two magnitudes of a continuous quantity stand in relation to one another as a ratio, which is a real number.