Lewis & Short

interstĭtĭum, i, n. [intersisto], a space between, interstice, interval (post-Aug.).

  1. I. Of place, Macr. Somn. Scip. 1, 6; Mart. Cap. 8, § 837; Amm. 20, 3, 10.
  2. II. Of time, an interval: quantum interstitii dies habet, Mart. Cap. 6, § 601.
    Plur., Mart. Cap. 6, § 600.