Lewis & Short

cōpŭla, ae (contr. form cōpla, in Wernsd. Poët. Lat. Min. IV. p. 535), f. [coapio], that which binds together or binds fast, a band, rope, thong, tie (rare; not in Cic.).

  1. I. Lit.: tortae, ship’s rigging, Att. ap. Non. p. 200, 33 (Trag. Rel. v. 577 Rib.); Plaut. Ep. 5, 1, 11: copulā vinctum ante se Thynem agere, Nep. Dat. 3, 2; cf.: copula dura canem tenet, a leash, Ov. Tr. 5, 9, 28; id. M. 7, 769; App. M. 7, p. 769: pectora copulae sparteae triturā continuā exulcerati (muli), id. ib. 9, p. 224 fin.
    Of the clasp of a bracelet, Capitol. Max. Jun. 1, 8.
    Of grapnel-hooks, etc., by which vessels were held in battle: eādem de causā minus commode copulis continebantur (naves), Caes. B. G. 3, 13 ex conj. (MSS. scopulis).
  2. II. Trop., a bond, tie, connection; of love: irrupta tenet, Hor. C. 1, 13, 18: nuptialis, App. M. 2, p. 120; so, copula, Dig. 5, 4, 24; 5, 4, 26; cf.: (Hymenaee), copula sacra deum, Mart. Cap. 1, § 1 Kopp ad loc.
    Of friendship: talium virorum, Nep. Att. 5, 3.
    Of words, Quint. 7, 10, 17; Nigid. ap. Gell. 10, 5, 1: ut dignitas eloquendi copulationis ipsius decore servetur, Mart. Cap. 5, § 509.