Treble  —adj. 1 a threefold. B triple. C three times as much or many (treble the amount). 2 high-pitched. —n. 1 treble quantity or thing. 2 hit on the narrow band between the two middle circles of a dartboard, scoring treble. 3 a mus. = *soprano (esp. A boy's voice or part, or an instrument). B high-pitched voice. 4 high-frequency output of a radio, record-player, etc. —v. (-ling) make or become three times as much or many; increase threefold; multiply by three.  trebly adv. [latin: related to *triple]