sphen- combining form orspheno- Etymology: New Latin, from Greek sphēn-, sphēno-, from sphēn — more at spoon 1.: wedge : wedge-shaped < sphenogram > < Sphenodon > 2. a.: of or relating to the sphenoid < sphenotribe > b.: sphenoidal and < sphenomastoid > < sphenethmoidal >