outer enclosure; outer fence; outer block
Refers to the outermost surrounding structure or area, such as a fence, wall, or designated block. Often used in architectural, urban planning, or military contexts.
The outer enclosure of the castle is surrounded by stone walls.
As an outer-block organization, it supports the city's projects.
Used for the outer shape or boundary of an object, plan, or concept. Less common than sense 1 and often replaced by 輪郭 (りんかく) in everyday language.
I explained only the outline of the plan.
That moat forms the outer boundary of the castle.
The foundation was established as an affiliated organization of the ministry.