Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
arcŭātus, a, um.
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.