(idiomatic) A numbers game: the use of inappropriate statistics (numbers) to reflect a desired result (usually misleading). / plural of number game: lotteries, numbers games.

(computing) Any computing application that requires large amounts of numerical calculation.

A phone number as a mnemonic whose letters translate into numbers.

(mathematics) A mathematician who specializes in number theory

plural of number theorist

A performance rating of diesel fuel corresponding to the percentage of cetane in a mixture with isocetane (or, formerly, methylnaphthalene) that would have the same performance.

(Canada, US) A telephone number for which an extra charge is assessed, part of which is returned to the owner of the number.

(rugby) A player in the scrum, who controls the movement of the scrum, and can pick up the ball exiting the scrum; eighthman. / (cricket) The batsman who bats eighth.

(Britain) Either of a pair of rectangular metal plates bearing an alphanumeric code, fixed to the front and rear of a motor car to show its identity as registered with the DVLA.

(graph theory) the number of vertices in a maximum independent set of a given graph, often denoted as 𝛼=𝛼(G)