Lewis & Short

explōrātĭo, ōnis, f. [exploro],

  1. I. an examination, exploration (post-Aug.): surculi, Col. 3, 9, 5: exploratione occulta fallere aliquem, Tac. H. 3, 54.
  2. II. In partic., in milit. lang., a spying, Dig. 49, 16, 3.