Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† ĕlătērĭum, ii, n., = ἐλατήριον, a medicine prepared from the juice of the wild cucumber, Cels. 5, 12; 6, 5; Scribon. Comp. 70, 224; Plin. 20, 1, 3, § 5 al.