The Collaborative International Dictionary of English v.0.48:

Philadelphian \Phil`a*del"phi*an\, a. [Gr. filadelfia brotherly
   love, from fila`delfos brotherly; fi`los loved, loving,
   friendly + 'adelfo`s brother.]
   Of or pertaining to Ptolemy Philadelphus, or to one of the
   cities named Philadelphia, esp. the modern city in
   Pennsylvania.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Philadelphian \Phil`a*del"phi*an\, n.
   1. A native or an inhabitant of Philadelphia.
      [1913 Webster]

   2. (Eccl. Hist.) One of a society of mystics of the
      seventeenth century, -- called also the Family of Love.
      --Tatler.
      [1913 Webster]