See Trass.
1. Swelling by a regular curve or surface; protuberant; convex; as, the moon is gibbous between the half-moon and the full moon. The bones will rise, and make a gibbous member. Wiseman. 2. Hunched; hump-backed. [Obs.] Sir T. Browne. -- Gib"bous*ly, adv. -- Gib"bous*ness, n.