realm
n. countablen. an area of activity, interest, or knowledge. It can also mean a kingdom ruled by a king or queen.
n. a primary sector of activity, interest, or thought; a kingdom or domain. Often used figuratively to describe abstract categories of knowledge or experience.
That question is outside the realm of my expertise.
The discovery of the new particle opened up possibilities that were previously only found in the realm of science fiction.
While the physical realm is governed by the laws of thermodynamics, the digital realm operates under a different set of constraints regarding scarcity and reproduction.
From Middle English rewme, realme, reaume, from Old French reaume, realme, reialme (“kingdom”), of unclear origins. A postulated *rēgālimen (“domain, kingdom”), Late Latin or Vulgar Latin cross of regimen with rēgālis is usually cited. The modern spelling predominates from around 1600. The modern pronunciation with /l/ is either a spelling pronunciation or influenced by the etymology.
Commonly used in the phrase 'in the realm of' followed by an abstract noun.