Source : Webster's Revised Unabridged Dictionary (1913)

Nicene \Ni"cene\, a. [L. Nicaenus, fr. Nicaea Nice, Gr. ?.]
   Of or pertaining to Nice, a town of Asia Minor, or to the
   ecumenial council held there A. D. 325.

   {Nicene Creed}, a summary of Christian faith, composed and
      adopted by the Council of Nice, against Arianism, A. D.
      325, altered and confirmed by the Council of
      Constantinople, A. D. 381, and by subsequent councils.

Source : WordNet®

Nicene Creed
     n : (Christianity) a formal creed summarizing Christian beliefs;
         first adopted in 325 and later expanded