orbĭcŭlus, i, m. dim. [orbis],
a small disk; a sheave , roller , pulley , etc. (anteclass. and post-Aug.), Cato R. R. 3, 6; 22, 2; Col. 4, 30, 4; Vitr. 10, 5: radix concisa in orbiculos, cut in little disks or slices , Plin. 25, 13, 94, § 148; Inscr. Orell. 2519.— Esp., the nave of a wheel , Vitr. 10, 2, 9.