The Collaborative International Dictionary of English v.0.48:

Nicene \Ni"cene\, a. [L. Nicaenus, fr. Nicaea Nice, Gr. ?.]
   Of or pertaining to Nice, a town of Asia Minor, or to the
   ecumenical council held there a. d. 325.
   [1913 Webster]

   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.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Creed \Creed\ (kr[=e]d), n. [OE. credo, crede, AS. creda, fr. L.
   credo I believe, at the beginning of the Apostles' creed, fr.
   credere to believe; akin to OIr. cretim I believe, and Skr.
   [,c]raddadh[=a]mi; [,c]rat trust + dh[=a] to put. See Do,
   v. t., and cf. Credo, Grant.]
   1. A definite summary of what is believed; esp., a summary of
      the articles of Christian faith; a confession of faith for
      public use; esp., one which is brief and comprehensive.
      [1913 Webster]

            In the Protestant system the creed is not coordinate
            with, but always subordinate to, the Bible.
                                                  --Schaff-Herzog
                                                  Encyc.
      [1913 Webster]

   2. Any summary of principles or opinions professed or adhered
      to.
      [1913 Webster]

            I love him not, nor fear him; there's my creed.
                                                  --Shak.
      [1913 Webster]

   Apostles' creed, Athanasian creed, Nicene creed. See
      under Apostle, Athanasian, Nicene.
      [1913 Webster]

WordNet (r) 3.0 (2006):

Nicene Creed
    n 1: (Christianity) a formal creed summarizing Christian
         beliefs; first adopted in 325 and later expanded