(idiomatic) A person who holds a position in an organization that corresponds to that held by another person in another organization; a counterpart

plural of whole number

(Firearms, on a bolt action rifle), corresponding serial numbers on both the removable bolt and the frame of the rifle.

The house number painted on the curb of the street in front of a building.

To queue; to wait to be served by being assigned a number and waiting for that number to be called after all previous numbers have been served in order of assignment.

The number of protons in an atom.

(mathematics) A number that represents the number of items in a pyramid having a given number of sides and layers

(physics) A quantum number related to the difference between the number of leptons and antileptons in a system

Alternative spelling of wavenumber

(number theory) A (nonzero) natural number that is expressible as the product of two (or more) natural numbers other than itself and 1.