Merriam-Webster's Collegiate® Dictionary, 11th Edition
CATHEDRAL
I. adjective
Date: 14th century
of, relating to, or containing a cathedra, emanating from a chair of authority, suggestive of a cathedral ,
II. noun
Date: 1587
a church that is the official seat of a diocesan bishop, something that resembles or suggests a cathedral (as in size or importance)