Tossing \Toss"ing\, n. 1. The act of throwing upward; a rising and falling suddenly; a rolling and tumbling. 2. (Mining) (a) A process which consists in washing ores by violent agitation in water, in order to separate the lighter or earhy particles; -- called also {tozing}, and {treloobing}, in Cornwall. --Pryce. (b) A process for refining tin by dropping it through the air while melted.