Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
* 1. rusco or rusto, āre, v. a. [ruscum], to clear of butcher’s-broom, Tert. Pall. 2.
2. rusco, ōnis, m., a disease of cattle, Gargil. Mart. de Cur. Boum.