Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
ridica, ae, f. In agriculture, a stake, prop, a vine-prop, Cato, R. R. 17; 1; Varr. R. R. 1, 8, 4; 1, 26; Col. 4, 26, 1; 11, 2, 12 al.