Definition of "permutation"

One of the ways something exists, or the ways a set of objects can be ordered.  examples

(mathematics) A one-to-one mapping from a finite set to itself.  examples

(mathematics, combinatorics) An ordering of a finite set of distinct elements.  examples

(music) A transformation of a set's prime form, by applying one or more of certain operations, specifically, transposition, inversion, and retrograde.  examples