The Collaborative International Dictionary of English v.0.48:

Cathedral \Ca*the"dral\, n. [LL. cathedralis (sc. ecclesia): cf.
   F. cath['e]drale. See Cathedra.]
   The principal church in a diocese, so called because in it
   the bishop has his official chair (Cathedra) or throne.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Cathedral \Ca*the"dral\, a. [LL. cathedralis: cf. F.
   cath['e]dral.]
   [1913 Webster]
   1. Pertaining to the head church of a diocese; as, a
      cathedral church; cathedral service.
      [1913 Webster]

   2. Emanating from the chair of office, as of a pope or
      bishop; official; authoritative.
      [1913 Webster]

            Now, what solemnity can be more required for the
            pope to make a cathedral determination of an
            article!                              --Jer. Taylor.
      [1913 Webster]

   3. Resembling the aisles of a cathedral; as, cathedral walks.
      --Pope.
      [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

25 Moby Thesaurus words for "cathedral":
   accepted, approved, authentic, authoritative, basilica, bethel,
   cathedral church, church, church house, conventicle, duomo,
   ex cathedra, house of God, house of prayer, house of worship, kirk,
   magisterial, meetinghouse, minor basilica, mission, official,
   patriarchal basilica, place of worship, received, standard