Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
corrīvātĭo (conr-), ōnis, f. [corrivo], a drawing together of streams of water (Pliny): aquae pluviae, Plin. 31, 3, 27, § 44; 33, 4, 21, § 74; 36, 15, 24, § 124.