Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
curcŭlĭo (gurgŭlĭo, Plaut. Trin. 4, 3, 9 Ritschl, Fleck.; Pall. 1, 19, 2; id. Jun. 3; also in some MSS. of the authors cited infra), ōnis, m. [kindr. with circulus, circus],