olemus
(3a) Internetis:
halduslikult ühtne kogum võrgustatud arvuteid,
mille täisdomeeninimedes on ühine sufiks

Merriam-Webster:
10 computers : a subdivision of the Internet consisting of computers or sites usually with a common purpose (such as providing commercial information) and denoted in Internet addresses by a unique abbreviation (such as com for commercial sites or gov for government sites)
//The domain ca is used for sites located in Canada.
https://www.rfc-editor.org/rfc/rfc920.txt
https://en.wikipedia.org/wiki/List_of_Internet_top-level_domains

(3b) IEC 732-01-31:
arvutivõrgu osa, mille ressursid ja adresseerimine
on mingi asjakohase organi kontrolli all;
domeenijaotus võib olla geograafiline või organisatsiooniline
=
part of a computer network in which resources or addressing are under control of a specific authority
Note. The domain scheme may be geographical or organizational.

https://en.wikipedia.org/wiki/Network_domain

vt ka
- domeen (2)
- domeeninimesüsteem