noun
old building; older building
Refers to a building that is older, often in contrast to a newer building (新館) on the same site, such as a school, hospital, or hotel wing.
この病院の旧館は来年取り壊される予定です。
The old building of this hospital is scheduled to be demolished next year.
旧館と新館は渡り廊下でつながっています。
The old building and the new building are connected by a covered walkway.
Compound of 旧 (former, old) and 館 (building, hall). The reading きゅうかん follows standard on'yomi.