1350-1400;Middle Englishcombinacyoun (< Middle French) < Late Latincombīnātiōn- (stem of combīnātiō), equivalent to combīnāt(us) combined (see combine, -ate^{1}) + -iōn--ion
an alliance of people or parties; group having a common purpose
4.
the set of numbers that opens a combination lock
the mechanism of this type of lock
5.
(Brit) a motorcycle with a sidecar attached
6.
(maths)
an arrangement of the numbers, terms, etc, of a set into specified groups without regard to order in the group: the combinations of a, b, and c, taken two at a time, are ab, bc, ac
a group formed in this way. The number of combinations of n objects taken r at a time is n!/[(n – r)!r!]. Symbol: nCrCompare permutation (sense 1)
7.
the chemical reaction of two or more compounds, usually to form one other compound
8.
(chess) a tactical manoeuvre involving a sequence of moves and more than one piece
late 14c., combinacyoun, from Old French combination (14c., Modern French combinaison), from Late Latin combinationem (nominative combinatio) "a joining two by two," noun of action from past participle stem of combinare (see combine (v.)).
1. A set containing a certain number of objects selected from another set. The number of combinations of r objects chosen from a set of n is n C r = n! / ((n-r)! r!) where "n C r" is normally with n and r as subscripts or as n above r in parentheses. See also permutation. 2. In the theory of combinators, a combination denotes an expression in which function application is the only operation. (1995-04-10)