Source : Webster's Revised Unabridged Dictionary (1913)

Interdenominational \In`ter*de*nom`i*na"tion*al\, a.
   Occurring between or among, or common to, different
   denominations; as, interdenominational fellowship or belief.

Source : WordNet®

interdenominational
     adj : occurring between or among or common to different churches
           or denominations; "interchurch aid";
           "interdenominational cooperation between Methodists and
           Presbyterians" [syn: {interchurch}]