Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
sĭtŭla, ae, f. (masc. collat. form sĭtŭ-lus, Cato, R. R. 10, 2; 11, 3; Vitr. 10, 9 fin.; Fest. s. v. nanum, pp. 176 and 177 Müll.; Paul. Sent. 3, 7 fin.).