Lewis & Short

circumstantĭa, ae, f. [circumsto] (post-Aug. and rare).

  1. I. A standing round, a surrounding: hostium, Gell. 3, 7, 5: aquae, aëris, Sen. Q. N. 2, 7, 2 (as transl. of the Gr. ἀντιπερίστασις).
    1. * B. Concr., a surrounding circle, a band, troop: angelorum, Tert. Or. 3.
  2. II. Trop., the state, condition, circumstances, attribute, quality: rerum negotiorumque, Gell. 14, 1, 15; 14, 2, 2; Tert. Bapt. 17: hoc genus argumentorum sane dicamus ex circumstantiā, quia περίστασιν dicere aliter non possumus, * Quint. 5, 10, 104.