n. The act of uniting in a whole, or the state of being so united; a coming together so as to form a group, sum, product, etc.; especially, the union of related parts in a complex whole: as, a combination of wheels and springs in a watch; a combination of ideas; a combination of circumstances.n. The whole or complex thus formed; the product of combining: as, a soft combination of stops in organ-playing.n. Specifically The union or association of two or more persons or parties for the attainment of some common end; a league: as, a political or a criminal combination; success is possible only through combination.n. In chem., chemical union; the production of a chemical compound.n. In mathematics, the union of a number of individuals in different groups, each containing a certain number of the individuals.n. At ball-pool, a designed shot by which a cue-ball makes one or more object-balls drive another into a pocket; at ordinary billiards one that similarly effects a carom or pocket.n. In lace-manufacture, a complex arrangement of threads.n. Same as combination-room.n. Same as combination garment.n. Specifically, in organ-playing, whatever stops are drawn for use in a particular piece or passage, or the tonal effect thus produced. The process or art of choosing the stops to be used is registration, but each particular choice is a combination.