Lewis & Short

sŏcĭālis, e, adj. [socius], of or belonging to companionship.

  1. I. In gen., companionable, sociable, social (so not ante-Aug.): homo sociale animal, Sen. Ben. 7, 1, 8: beneficium dare socialis res est, id. ib. 5, 11, 4: amicitiae, App. M. 5, p. 171, 20.
  2. II. In partic.
    1. A. Of or belonging to allies or confederates, allied, confederate (the class. signif. of the word): lex, Cic. Div. in Caecil. 5, 18: lex judiciumque, id. Verr. 2, 2, 6, § 15: foedus, Liv. 34, 57: exercitus, i. e. of the allies, id. 31, 21: coetus, id. 7, 25: equitatus, id. 26, 5; so, turmae, Tac. A. 4, 73: copiae (opp. legiones), i. e. auxiliaries, id. ib. 12, 31: bellum, the war of the allies, Liv. Epit. 71 fin.; Flor. 3, 18, 1; Juv. 5, 31: cuncta socialia prospere composita, the affairs of the allies, Tac. A. 2, 57.
    2. B. In Ovid several times like conjugialis, of marriage, conjugal, nuptial: amor socialis, Ov. M. 7, 800; (with foedus maritum), id. P. 3, 1, 73: Livia sic tecum sociales compleat annos, id. Tr. 2, 161: foedera, id. M. 14, 380; id. H. 4, 17: torus, id. F. 2, 729: jura, id. Am. 3, 11, 45: sacra, id. H. 21, 155: carmina, i. e. epithalamium, id. ib. 12, 139.
      Hence, adv.: sŏ-cĭālĭter, socially: non ut de sede secundā Cederet aut quartā socialiter (iambus), for the sake of company (perh. ἅπ. εἰρημ.), Hor. A. P. 258.