Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
occātĭo, ōnis, f. [occo], a harrowing (class.): terra semen occaecatum cohibet: ex quo occatio, quae hoc efficit, nominata est, Cic. Sen. 15, 51; Col. 11, 2, 62; Plin. 18, 20, 49, § 180.