1. An ancient city northeast of the Dead Sea in modern-day Jordan. The chief city of the Ammonites, it was enlarged and embellished by Ptolemy II Philadelphus (285-246 BC) and named in honor of him. Amman, the capital of Jordan, is now on the site.

2. An ancient Greek city of Asia Minor in present-day western Turkey. Founded in the second century BC, Philadelphia was a center of early Christianity.

3. The largest city of Pennsylvania, in the southeast part of the state on the Delaware River. It was founded as a Quaker colony by William Penn in 1681 on the site of an earlier Swedish settlement. The First and Second Continental Congresses (1774 and 1775-1776) and the Constitutional Convention (1787) met in the city, which served as the capital of the United States from 1790 to 1800.