Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
porrum, i, n., and porrus, i, m. [πράσον], a leek, scallion; of two kinds, capitatum and sectile, the latter our chives, Col. 8, 11, 14; Plin. 19, 6, 33, § 108; Mart. 3, 47, 8; 3, 13, 18; 19; Juv. 3, 293; 14, 133.