Lewis & Short

† causĭa, ae, f., = καυσία,

  1. I. a Macedonian white hat with a broad brim, worn in Rome by the poorer people, as a protection against the sun, Plaut. Mil. 4, 4, 42; id. Pers. 1, 3, 75; Val. Max. 5, 1, 4; Mart. 14, 29.
    Hence,
  2. II. In milit. lang., a kind of roof for the protection of besiegers, = vinea, Veg. Mil. 4, 15.