enclosure
Definitions
An area that is sealed off with an artificial or natural barrier.
The act of surrounding something or the state of being enclosed.
A document or object included within a letter or package.
Examples
The zookeeper carefully checked the gate of the lion's enclosure to ensure it was locked.
Please find the requested documents in the enclosure attached to this email.
The ancient ruins were protected by a stone enclosure that had stood for centuries.