Lewis & Short

fossūra, ae, f. [fodio], a digging (postAug., whereas fossio is quite class.).

  1. I. Lit.: plana fossura, Col. 4, 14, 2; Pall. 10, 14, 2.
    In plur.: complanata juga fossuris montium, Suet. Calig. 37: puteorum, Vitr. 5, 9, 8; Col. 4, 28, 2.
  2. II. Transf., concr., a pit: summa fossura operiatur arundinibus, Vitr. 8, 1, 4.