Other forms: realms
A realm is a kingdom, or a field of activity. The realm of possibility, defend the realm, in the realm of science.
In British law the realm means the kingdom itself, and defence of the realm is the formal phrase. The figurative use is now commoner — within the realm of possibility means possible, though it takes seven words to say it.
1nounkingdomA kingdom.
“The king sent soldiers to every corner of the realm.”
2nounrealmA field of activity.
“The discovery opened up a whole new realm of medical research.”
Too few real examples of this word to estimate which sense is commonest.
realm is a kingdom, or a field.
Underneath it is the same word as royal. A realm is what a king rules, and later on any ground somebody rules.
hooks ontoroyal
Old French realme means a kingdom, from Latin regalis, royal, from rex, a king. Regal and royal are relatives.
Proto-Indo-European
*h₃reǵ-
Old French
reaume
Middle English
rewme
English, today
realm
Built from
From Middle English rewme, realme, reaume, from Old French reaume, realme, reialme (“kingdom”), of unclear origins. A postulated rēgālimen (“domain, kingdom”), Latin - or Vulgar Latin - cross of regimen with rēgālis is usually cited. The modern spelling predominates from around 1600. The modern pronunciation with is either a spelling pronunciation or influenced by the etymology.
Etymology from Wiktionary, CC BY-SA