C / circĕs
noun

circĕs

gen. circitis · gender masculine · decl. 3rd
circum-ire
a circle; the circumference of the circus
a circle (ante- and post-class.): ut parvi circuli Anuli, sic magni dicebantur circites Ani, Varr L. L. 6, § 8 Müll.; Sid. Carm. 22, 222. —So of the circumference of the circus, Sid. Carm. 23, 381.