(mathematics) Any of several complex numbers that are coordinates of the vertices of a regular polygon of unit radius

(genetics) A DNA sequence, 1000 nucleotides (or synonymously base pairs) in length or longer, that is present a variable number of times as copies in a genome relative to a reference genome.

(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

(euphemistic, usually childish) Feces; the act of defecation. / (nautical, slang) A first mate. / A primary assistant; vice-leader.

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

A memorable mobile phone number.

(chemistry, physics) The number of atoms present in 12 grams of isotopically pure carbon-12, being 6.02214076 × 10²³. By definition, the number of elementary entities (atoms or molecules) comprising one mole of a given substance.

(physics) A dimensionless parameter that determines the behavior of viscous flow patterns. In pipe flow a value less than about 2,000 (known as the critical Reynolds number) produces laminar flow, one above about 3,000 produces turbulent flow (intermediate values produce unpredictable behavior).

(Canada, US) A toll-free telephone number.