Lewis & Short

Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.

pĕlăgĭum, ii, v. pelagius, II. B.

      1. 1. † pĕlăgĭus, a, um, adj., = πελάγιος, of or belonging to the sea, sea- (pure Lat. marinus): pelagii greges piscium, Varr. R. R. 3, 3, 10: pelagiae conchae, sea-mussels, Plin. 9, 29, 46, § 85: cursus, Phaedr. 4, 20, 7: matrona ornata phaleris pelagiis, i. e. with pearls and corals, P. Syrus ap. Petr. 55
  1. II. Subst.
    1. A. pĕlăgĭa, ae, f., a kind of pearl-mussel, Plin. 9, 37, 61, § 131.
    2. B. pĕ-lăgĭum, ii, n., purple color, Plin. 9, 38, 62, § 134; 9, 40, 64, § 138.

2. Pĕlăgĭus, ii, m., a famous heretic of the fifth century A. D., Aug. Ep. 175; id. Haeres. 88.
Hence, Pĕlăgĭānus, i, m., a follower of Pelagius, Isid. Orig. 8, 5, 63.