Lewis & Short

congrĕgātĭo, ōnis, f. [congrego], an assembling together; union, society, association (in good prose).

  1. I. Lit.: nos ad conjunctionem congregationemque hominum et ad naturalem communitatem esse natos, Cic. Fin. 3, 20, 65; 4, 2, 4; cf. Sen. Ep. 5, 3; Cod. Th. 18, 14, 4 al.
  2. II. Trop.: argumentorum (corresp. with colligere), Quint. 5, 7, 18: criminum (opp. separatio), id. 7, 1, 31: rerum (with repetitio, Gr. ἀνακεφαλαίωσις), a recapitulating, id. 6, 1, 1: personarum, locorum, temporum, id. 3, 5, 17.