Lewis & Short

scămillus, i, m. (acc. to Prisc. p. 615 P., scămellum, i, n.) dim. [scamnum], a little bench or stool: impares, i. e. unequal projections or steps on the pedestals of columns, Vitr. 3, 4, 5; 5, 9, 4; App. 615 P.