Lewis & Short

Permessus, i, m., = Περμησσός, a river in Bœotia sacred to Apollo and the Muses, which rises in Mount Helicon and flows into the Copaic lake, Verg. E. 6, 64.
Hence,

  1. A. Permessis, ĭdis or ĭdos, adj. f., Permessian, Mart. 1, 77, 11; 8, 70, 3.
  2. B. Permessĭus, a, um, adj., Permessian: fons, Claud. Laud. Seren. 8.