The headword, genitive plural of this adjective, is extracted from the quotation given (its only attestation outside lexicography): Greek Anthology 6.231.4 (Philip).
A 'yoke' means, by transference, any matched pair: see generally LSJ s.v. zeu=gos, II (web address 1).
On this epigram, the seafarer Damis's dedication and prayer to an unnamed Egyptian goddess, see Gow and Page (vol. I, 310-313); (vol. II, 344-345); and further excerpts from this epigram at alpha 4223, kappa 1222, kappa 1310, lambda 13, mu 447, and psi 31. The aquatic geese that Damis consecrates are evidently not domestic. The LSJ s.v. xh/n (web address 2) identifies the bird as Anser cinereus, now Anser anser (Greylag Goose), the ancestor of modern domestic geese. Gow and Page note (vol. II, 344) that these geese were commonly sacrificed to Isis (and Osiris), that Isis was widely worshipped in Greek and Roman lands at this time (ibid.), and that Isis was a protector of sailors (vol. II, 345)--all of which gesture at Isis as the goddess whom Damis addresses.