\Com`bi*na"tion\, n. [LL. combinatio. See
{Combine}.]
1. The act or process of combining or uniting persons and
   things.
         Making new compounds by new combinations. --Boyle.
         A solemn combination shall be made Of our dear
         souls.                                --Shak.
2. The result of combining or uniting; union of persons or
   things; esp. a union or alliance of persons or states to
   effect some purpose; -- usually in a bad sense.
         A combination of the most powerful men in Rome who
         had conspired my ruin.                --Melmoth.
3. (Chem.) The act or process of uniting by chemical
   affinity, by which substances unite with each other in
   definite proportions by weight to form distinct compounds.
4. pl. (Math.) The different arrangements of a number of
   objects, as letters, into groups.
Note: In combinations no regard is paid to the order in which
      the objects are arranged in each group, while in
      variations and permutations this order is respected.
      --Brande & C.
{Combination car}, a railroad car containing two or more
   compartments used for different purposes. [U. S.]
{Combination lock}, a lock in which the mechanism is
   controlled by means of a movable dial (sometimes by
   several dials or rings) inscribed with letters or other
   characters. The bolt of the lock can not be operated until
   after the dial has been so turned as to combine the
   characters in a certain order or succession.
{Combination room}, in the University of Cambridge, Eng., a
   room into which the fellows withdraw after dinner, for
   wine, dessert, and conversation.
{Combination by volume} (Chem.), the act, process, or ratio
   by which gaseous elements and compounds unite in definite
   proportions by volume to form distinct compounds.
{Combination by weight} (Chem.), the act, process, or ratio,
   in which substances unite in proportions by weight,
   relatively fixed and exact, to form distinct compounds.
   See {Law of definite proportions}, under {Definite}.
Syn: Cabal; alliance; association; league; union;
     confederacy; coalition; conspiracy. See {Cabal}.