The number of people, statistically, who must be exposed to something in order for one of them to experience an adverse effect.

(Stephanus pagination) A standard reference number for a section of a given Platonic dialogue, referring to a page in the 1578 translation of Plato’s dialogues by Henricus Stephanus.

(somewhat rare) A number theorist.

plural of number theoretician

(physics) The number of electrons in an atom or ion

plural of defective number

plural of excessive number

Alternative form of what's your phone number?

(informal) stupid.

plural of back number