Lewis & Short

Pharsālos or Pharsālus, i, f., = Φάρσαλος, a city in Thessaly, where Cœsar defeated Pompey, now Fersala, Liv. 32, 33; 34, 23; 36, 14; Luc. 6, 350.
Hence,

  1. A. Pharsālĭcus, a, um, adj., of or belonging to Pharsalus, Pharsalian: acies, Cic. Phil. 2, 29, 71: proelium, Cœsar’s victory over Pompey, id. Deiot. 5, 13; 10, 29: acies, id. Lig. 3, 9: annus, Luc. 5, 391: rura, id. 7, 823.
  2. B. Pharsālĭus, a, um, adj., Pharsalian: fuga, Cic. Phil. 2, 15, 39: pugna, in which Cœsar defeated Pompey, id. ib. 14, 8, 23 B. and K.; id. Div. 1, 32, 68; Plin. 8, 16, 21, § 53: terra, Liv. 33, 6, 11: tecta, Cat. 64, 37.
    As subst.: Pharsālĭa, ae, f., the region about Pharsalus, Cat. 64, 37; Ov. M. 15, 823; Tac. H. 1, 50 al.
    1. 2. An epic poem by Lucan, Luc. 7, 61; 9, 985.