subdomain

About 0.15 uses per million words.

Meaning

1. noun A domain or sphere that is part of a larger domain or sphere.
2. noun A domain name that has been prefaced with additional parts separated with periods.
3. noun An additional part prefaced to a domain name.

   In en.wiktionary.org, en is a subdomain.

Similar words

subsubdomain undersphere subworld subcommunity subsector subzone sublocation subsegment subregion subarea

Often followed by

of is and in to are for with name