Source : Webster's Revised Unabridged Dictionary (1913)

Combine \Com*bine"\, v. i.
   1. To form a union; to agree; to coalesce; to confederate.

            You with your foes combine, And seem your own
            destruction to design                 --Dryden.

            So sweet did harp and voice combine.  --Sir W.
                                                  Scott.

   2. To unite by affinity or natural attraction; as, two
      substances, which will not combine of themselves, may be
      made to combine by the intervention of a third.

   3. (Card Playing) In the game of casino, to play a card which
      will take two or more cards whose aggregate number of pips
      equals those of the card played.

   {Combining weight} (Chem.), that proportional weight, usually
      referred to hydrogen as a standard, and for each element
      fixed and exact, by which an element unites with another
      to form a distinct compound. The combining weights either
      are identical with, or are multiples or submultiples of,
      the atomic weight. See {Atomic weight}, under {Atomic}, a.

Source : WordNet®

combining weight
     n : the atomic weight of an element that has the same combining
         capacity as a given weight of another element; the
         standard is 8 for oxygen [syn: {equivalent}, {equivalent
         weight}, {eq}]