Dom.

15th-century alteration (see below) of older Thum, from Middle High German and Old High German tuom, from Proto-West Germanic *dōm (whence Old Dutch duom, Middle Low German dôm), from Medieval Latin domus (literally “house”). The use probably goes back to domus episcopatus/episcopalis (“house of the bishopric”). An alternative theory derives it from domus ecclesiae (“church house”), after Ancient Greek οἶκος τῆς ἐκκλησίας (oîkos tês ekklēsías). The modern alteration Dom follows Middle French dome, from Italian duomo, from the Latin. It was probably reinforced by the inherited Middle Low German form (see above). Thum survived longest in the south. The Dutch cognate dom was similarly influenced by French.