permutation, per mut a cion

[Fr. per mutation, from Lat. permutationem, acc. of permu tatio a changing, from per mut at us, pa. par. of permuto =to permute (q.v.). Sp.per mut a cion; Ital. per mut azione.] *1. Ord . Lang .: The act of exchanging one thing for another; mutual change; interchange; inter mutation. "A permutation of number is pregnant in languages." -Bentley. 2. Math .: Change or combination of any number of quantities. The different arrangements which can be made of any number of given quantities, when a certain number, or the whole of them, are taken together; thus the permutations of a , b , and c, taken two together, are ab , ac , ba , be , ca , and cb . The number of permutations of n things taken two together is n (n-1); of n things taken three together, n (n-1)(n-2), and so on. permutation-lock, s. Locksmith.: A lock in which the moving parts are capable of transposition, so that, being arranged in any concerted order, it becomes nece ary, before shooting the bolt, to arrange the tumblers. [LETTER-LOCK.]