Philadelphian adjective 2noun 2forms 3 adjective2 •Of or relating to Philadelphia. •Of or relating to the ancient king Ptolemy II Philadelphus. noun2 •A person who originates from or lives in Philadelphia.My grandmother was a Philadelphian, having come out from that city after the war. — 1932 •(historical) A member of a 17th-century Protestant religious group in England. formsPhiladelphians · more Philadelphian · most Philadelphian