noun, noun which may take the genitive case particle 'no'
outside the building; off the premises
Used for areas outside a specific facility such as a library, museum, or hall. Often appears in signs or rules.
Please refrain from eating and drinking outside the building.
この資料は館外貸出ができません。
This material cannot be checked out of the library.
Compound of 館 (kan, 'building, hall') and 外 (gai, 'outside').