(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.

(astronomy) A catalogue number used to identify any one of more than one hundred galaxies, nebulae, and other deep-sky objects visible in the night sky; the designation formed by the surname Messier or letter M being prepended to the number, as in Messier 31 or M31 (the Andromeda Galaxy).

(chemistry) the number of molecules that are associated together to form a micelle

plural of deficient number

(informal) To damage; to treat harshly; to produce ill effects in.

To complete such an exercise; to carry out such a technique by filling in each space with the appropriate color.

alternative form of color by number / (rare) plural of color by number