Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
scalpellum, i, n. (collat. form scal-pellus, i, m., Cels. 2, 10 twice), dim. [scalprum], a small surgical knife, a scalpel, a lancet: scalpellum adhibere, Cic. Sest. 65, 135; id. Div. 2, 46, 96; Col. 6, 32, 3; Plin. 28, 8, 28, § 110; Veg. Vet. 1, 26, 2; Sen. Ira, 2, 27, 4: scribae, a penknife, Vulg. Jer. 36, 23.