(mathematics) a positive integer

(library science) An identification number, usually consisting of a combination of numbers and characters, used to identify and locate materials within a library.

plural of abstract number

(mathematics) A positive integer that is the product of three distinct prime factors.

plural of prime number

Any of a range of European abbreviations for food additives used on labels. / (Britain, Ireland, informal) Any such additive, often regarded as undesirable.

(idiomatic) First; foremost; best, often used after its headword.

The most important person, the one who is in charge. / Someone who is top of a ranking, who is ranked first. / Oneself, being considered foremost, as by an egoist.

(physics) The number of neutrons or protons in nuclei which are required to fill the major quantum shells, and thus produce exceptionally stable nuclei: 2, 8, 20, 28, 50, 82 and 126.

A number used without application to things, e.g. 6, 8, 10; but when applied to anything, e.g. 6 feet, 10 men, it becomes concrete.