This is the 7512th most frequent Japanese word.
全館
"Entire building" or "whole building."
全館 refers to the entirety of the building or facility being closed.
全館が改修工事のため閉鎖されています。
The entire building is closed for renovation work.
全館 is used to describe the scope of decoration, indicating it's applied to the whole building.
大会の準備のため、全館を装飾しました。
For the preparation of the event, the entire building has been decorated.
全館 signifies that the power outage affected the whole building, not individual parts.