An extremely large number that is an upper bound on the solution to a certain problem in Ramsey theory.

A number that represents the reciprocal of the dispersive power of a substance with transparent qualities.

plural of abbreviated number

A number which has had significant figures omitted beyond a certain point to make calculations easier; rounded number.

plural of even number

(grammar) A grammatical number denoting a quantity of exactly two.

(combinatorics) Any one of a certain set of numbers which are guaranteed to exist by Ramsey's theorem; a positive integer which is a certain function of some given multiset of positive integers, where that "certain function" is that which yields the minimal number guaranteed to exist by Ramsey's theorem.

A shortwave radio station characterized by unusual broadcasts, often of artificially generated voices reciting streams of numbers, words, etc., supposed to be coded messages.

plural of broken number

(mathematics, obsolete) A fraction.