pos-i-do'-ni-us (Posidonios, al. Posidonios and Poseidon): One of the three envoys sent by the Syrian general Nicanor to treat with the Jews under Judas during his invasion of Judea, 161 B.C. (2 Maccabees 14:19). In 1 Maccabees 7:27;, proposals are sent by Nicanor to Judas, but no envoys are named, and it is there asserted in contradiction to 2 Maccabees that Judas broke off the negotiation because of the treacherous designs of Nicanor.