Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
stŏrĕa (in good MSS. also stŏrĭa; cf. Caes. B. C. 2, 9), ae, f. [from the root ster, sterno; Gr. στοπέννυμι, to spread out], a mat or covering made of plaited straw, rushes, rope, etc.; a straw-mat, rush-mat, rope-mat, Caes. B. C. 2, 9; Liv. 30, 3; Plin. 15, 16, 18, § 59.