n. In the refining of metallic tin, the dipping up of the melted metal in ladles. and pouring it back into the pot whence it came, thus by exposure to the air causing oxidation of the foreign metals and other impurities which accumulate as a scum on the surface of the refined tin.n. The act or operation of one who or that which tosses; specifically, a mining process (also called chimming) which consists in dressing ores by the method described under toss, v. t., 3.