ETYM Old Eng. nombre, French nombre, Latin numerus.
1. A numeral or string of numerals that is used for identification; SYN. identification number.
2. A concept of quantity derived from zero and units.
3. An item of merchandise offered for sale.
4. The property possessed by a sum or total or indefinite quantity of units or individuals; SYN. figure.
5. A select company of people.
6. (Linguistics) The grammatical category for the forms of nouns and pronouns and verbs that are used depending on the number of entities involved (singular or dual or plural).
7. (Informal) A clothing measurement.
Symbol used in counting or measuring. In mathematics, there are various kinds of numbers. The everyday number system is the decimal (“proceeding by tens”) system, using the base ten. Real numbers include all rational numbers (integers, or whole numbers, and fractions) and irrational numbers (those not expressible as fractions). Complex numbers include the real and imaginary numbers (real-number multiples of the square root of -1). The binary number system, used in computers, has two as its base. The natural numbers, 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9, give a counting system that, in the decimal system, continues 10, 11, 12, 13, and so on. These are whole numbers (integers), with fractions represented as, for example, Ľ, ˝, ľ, or as decimal fractions (0.25, 0.5, 0.75). They are also rational numbers. Irrational numbers cannot be represented in this way and require symbols, such as Ö2, p, and e. They can be expressed numerically only as the (inexact) approximations 1.414, 3.142, and 2.718 (to three places of decimals) respectively. The symbols p and e are also examples of transcendental numbers, because they (unlike Ö2) cannot be derived by solving a polynomial equation (an equation with one variable quantity) with rational coefficients (multiplying factors). Complex numbers, which include the real numbers as well as imaginary numbers, take the general form a + bi, where i = Ö-1 (that is, i2 = -1), and a is the real part and bi the imaginary part.
Evolution of number systems.
The ancient Egyptians, Greeks, Romans, and Babylonians all evolved number systems, although none had a zero, which was introduced from India by way of Arab mathematicians in about the 8th century ad and allowed a place-value system to be devised on which the decimal system is based. Other number systems have since evolved and have found applications. For example, numbers to base two (binary numbers), using only 0 and 1, are commonly used in digital computers to represent the two-state “on” or “off” pulses of electricity. Binary numbers were first developed by German mathematician Gottfried Leibniz in the late 17th century.
Defining types of numbers.
Concepts such as negative number, rational number, and irrational number can be rigorously and precisely defined in terms of the natural numbers. There remains then the problem of defining the natural numbers. A modern approach defines the natural numbers in terms of sets. Zero is defined to be the empty set: 0 = Ć (i.e. the set with no elements). Then 1 is defined to be the union of 0 and the set that consists of 0 (which is a set with 1 element, zero). Now we can define 2 as the union of 1 and the set containing 1 (which is a set containing 2 elements, zero and one), and so on.
An alternative procedure for constructing a number system is to define the real numbers in terms of their algebraic and analytical properties.In grammar, the singular and plural forms of nouns, pronouns, and verbs.
1. To enumerate; SYN. list.
2. To give numbers to
3. To place a limit on the number of; SYN. keep down.