Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
arcella, ae, f. dim. [arca; cf. Paul. ex Fest. p. 21 Müll.]; among surveyors, a square landmark (cf. arca, II. F., and arcatura), Front. Colon. pp. 119, 260, 308 Goes.