I.a half-circle, semicircle, Vitr. 9, 8, 5; Plin. Ep. 5, 6, 33.—
II. In partic.
A. A semicircular recess, with seats, Cic. Lael. 1, 2; Sid. Ep. 2, 2.—
B. A semicircular public place furnished with rows of seats for learned discussions, Suet. Gramm. 17.—
C. A semicircular kind of sundial, Vitr. 9, 8, 1.