Lewis Short
(verb) : foedĕro, āvi, ātum, 1, 2. foedus
* To establish by treaty or league (in verb. finit., late Lat.): cum foederaretur concordia,Amm. 31, 4: pacem,id. 25, 7: amicitias,Hier. Ep. 5, 1; but class. in the part.: foedĕrātus, a, um, leagued together, confederated, allied: si qui foederatis civitatibus ascripti essent,Cic. Arch. 4, 7: civitates,Cic. Verr. 2, 3, 6, § 13: populus,id. de Or. 1, 40, 182; id. Balb. 8, 22; cf. absol.: ut omnium beneficiorum nostrorum expertes faciat foederatos,id. ib.: Mamertinorum foederatum atque pacatum solum,Cic. Verr. 2, 4, 11, § 26.
Charlton T. Lewis, Charles Short, A Latin Dictionary