the.com/realm

means A realm is a domain or sphere of activity, rule, or existence — a kingdom in the literal sense, or any area where something holds sway, like 'the realm of possibility.'

from From Old French 'reaume' or 'realme,' which grew out of Latin 'regimen' (rule, guidance) — the same root that gives us 'regime' and 'regal.' The underlying Latin verb 'regere' means 'to rule' or 'to keep straight,' linking realm to a whole family of words about governance and order. By the time it settled into English around the 13th century, it had come to mean a kingdom or the territory under a sovereign's rule — and later loosened its grip to cover any figurative domain, from the realm of dreams to the realm of possibility.