Lewis & Short

1. cŭbĭtus, ūs, m. [cubo], a lying down (very rare).

  1. I. Prop.: supini, proni, in latera, Plin. 28, 4, 14, § 54.
    1. B. Esp., of coitus (for concubitus), in plur., Plaut. Am. 5, 1, 70.
  2. II. Meton. (abstr. pro concr.), a bed, couch: foliis cubitus sibi sternunt, Plin. 24, 9, 38, § 59.