From cadeira (“chair”) + -ado.
cadeirado m (plural cadeirados)
- a building or room’s set of chairs or pews
1998, Ofelia Rey Castelao, A Galicia clássica e barroca, Galaxia, page 290:[…] , así como o cadeirado do mosteiro de Montederramo (160–8), […]- […] , as well as the chairs of Montederramo monastery (160–8), […]