Lewis & Short

arcŭo, āvi, ātum, 1, v. a. [arcus], to make in the form of a bow, to bend or curve like a bow (not before the Aug. per.): curru arcuato vehi, i. e. covered, Liv. 1, 21: opus, Plin. Ep. 10, 46, 2: (millepeda) quae non arcuatur, does not bend itself in the form of a bow, Plin. 29, 6, 39, § 137 (cf. arcuatim); Ov. M. 11, 590.