From WordNet (r) 3.0 (2006) [wn]:
duomo
n 1: the principal Christian church building of a bishop's
diocese [syn: cathedral, duomo]
From The Collaborative International Dictionary of English v.0.48 [gcide]: Duomo \Duo"mo\, n. [It. See Done.] A cathedral. See Dome, 2. [1913 Webster] Of tower or duomo, sunny sweet. --Tennyson. [1913 Webster]