noun
closed network; closed domain
Technical computing term for a network or domain that is not open to the public, such as a private LAN or a closed system.
このシステムは閉域ネットワークで運用されています。
This system operates on a closed network.
Compound of 閉 (へい, 'closed') and 域 (いき, 'area' or 'domain'). The exact historical derivation is uncertain, but the term is used in modern technical contexts.