co-cathedral
nounEtymology From co- + cathedral.
1
Christianity One of a group of churches (usually a pair) which share the function of being the seat of a bishop.
- Long before this day of contented stagnancy, in 1061, when Forcalquier, fortified, growing, and important, claimed many honours, Bishop Gérard Caprérius of Sisteron had given the city a Provost and a Chapter, and created the Church of Saint-Mary, co-cathedral with that of Notre-Dame of Sisteron. Not contented with this honour, Forcalquier demanded and received a Bishopric of her own.1906, Elise Whitlock Rose, Cathedrals and Cloisters of the South of France, volume 1: