Lewis & Short

com-mīlĭtĭum, ii, n. [militia], companionship in war (prob. not in use before the Aug. period).

  1. I. Prop., Veil. 2, 29, 5; * Quint. 5, 10, 111; Tac. A. 1, 60; Flor. 4, 4, 2; Just. 5, 10, 3; 11, 5, 3; Plin. Ep. 10, 11, 2; 10, 18, 1.
  2. II. Transf., fellowship, companionship in gen. (very rare): (studiorum), Ov. P. 2, 5, 72; App. Flor. 3, p. 356, 1; Manil. 1, 780.