Do you mean "what is a permutation"? A permutation of a given list is simply a rearrangement of the list. For example, if the original list is "abc" then permutations are "acb", "bac", "bca", "cab", "cba", and, for completeness, we include the orignal list, "abc" as a permutation.
we can define permutation as-
1.NUMBER OF ORDERED SELECTION OF "K" OBJECTS OUT OF "N" DISTINCT OBJECTS WITHOUT REPETITION.OR.;
2.ORDERED SAMPLING OF K OBJECTS OUT OF N DISTINCT OBJECTS WITHOUT REPLACEMENT.OR
3.NUMBER OF PERMUTATION(ORDERED SAMPLING)OF K OBJECTS OUT OF N DISTINCT OBJECTS WITHOUT REPETATION...