Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† hĕlops (also ĕlops and ellops), ŏpis, m., = ἔλλοψ, a very savory sea-fish, perh. the sword-fish; acc. to others, the sturgeon, Enn. Hed. 6 (p. 166 Vahl.); Ov. Hal. 96; Varr. R. R. 2, 6, 2; Col. 8, 16, 9; Plin. 9, 17, 27, § 61; 32, 11, 54, § 153; Quint. 5, 10, 21; Gell. 7, 16, 5.