A number is a mathematical object used in counting and measuring. A notational symbol which represents a number is called a numeral, but in common usage the word number is used for both the abstract object and the symbol, as well as for the word for the number. In addition to their use in counting and measuring, numerals are often used for labels (telephone numbers), for ordering (serial numbers), and for codes (ISBNs). In mathematics, the definition of number has been extended over the years to include such numbers as 0, negative numbers, rational numbers, irrational numbers, and complex numbers.
Certain procedures which take one or more numbers as input and produce a number as output are called numerical operations. Unary operations take a single input number and produce a single output number. For example, the successor operation adds one to an integer, thus the successor of 4 is 5. More common are binary operations which take two input numbers and produce a single output number. Examples of binary operations include addition, subtraction, multiplication, division, and exponentiation. The study of numerical operations is called arithmetic.
Anglo-Norman nombre, noumbre, numbre, nounbre, nunbre, numere and Old French, Middle French nombre sum, total (early 12th cent. as numbre), grammatical number (13th cent.), a (large, small) quantity (14th cent.), conformity in verse to a regular measure (1549) < classical Latin numerus sum, total, numeral, number as indicating a part or position in a series, a (large, small) quantity, a (large or small) group or collection of persons or things, a class or category, number as an abstract concept, the fact of being numerous, numerical calculation, arithmetic, rhythm in words or music, grammatical number, metrical foot, (plural) metrical lines, musical strains, perhaps < a suffixed ablaut variant of the same Indo-European base as ancient Greek (NOMOS n.).
- 1 an arithmetical value, expressed by a word, symbol, or figure, representing a particular quantity and used in counting and making calculations and for showing order in a series or for identification : she dialed the number carefully | an even number.
• ( numbers) dated arithmetic : the boy was adept at numbers.
- 2 a quantity or amount : the company is seeking to increase the number of women on its staff | the exhibition attracted vast numbers of visitors.
• ( a number of) several : we have discussed the matter on a number of occasions. • a group or company of people : there were some distinguished names among our number. • ( numbers) a large quantity or amount, often in contrast to a smaller one; numerical preponderance : the weight of numbers turned the battle against them.
- 3 a single issue of a magazine : the October number of “Travel.”
• a song, dance, piece of music, etc., esp. one of several in a performance : they go from one melodious number to another. • [usu. with adj. ] informal a thing, typically an item of clothing, of a particular type, regarded with approval or admiration : Yvonne was wearing a little black number.
- 4 Grammar a distinction of word form denoting reference to one person or thing or to more than one. See also singular (sense 2), plural , count noun , and mass noun .
• a particular form so classified.
Verb [ trans. ]
- 1. amount to (a specified figure or quantity); comprise : the demonstrators numbered more than 5,000.
• include or classify as a member of a group : the orchestra numbers Brahms among its past conductors.
- 2 (often be numbered) mark with a number or assign a number to, typically to indicate position in a series : each document was numbered consecutively.
• count : strategies like ours can be numbered on the fingers of one hand. • assess or estimate the size or quantity of (something) to be a specified figure : he numbers the fleet at a thousand.
- any number of any particular whole quantity of : the game can involve any number of players. • a large and unlimited quantity or amount of : the results can be read any number of ways.
by numbers following simple instructions identified by numbers or as if identified : painting by numbers.
- by the numbers following standard operating procedure. • all together with a shouted-out count. someone's/something's days are numbered someone or something will not survive or remain in a position of power or advantage for much longer : my days as director were numbered.
- do a number on informal treat someone badly, typically by deceiving, humiliating, or criticizing them in a calculated and thorough way.
- have someone's number informal understand a person's real motives or character and thereby gain some advantage.
- have someone's number on it informal (of a bomb, bullet, or other missile) destined to find a specified person as its target.
- someone's number is up informal the time has come when someone is doomed to die or suffer some other disaster or setback. ORIGIN: with reference to a lottery number or a number by which one may be identified.]
- without number too many to count : they forgot the message times without number.