realm

realm — noun

1. a particular broad field of knowledge, activity, or life that a person or group

1.nounB2
Definition

a particular broad field of knowledge, activity, or life that a person or group thinks about, deals with, or concerns themselves with

Example

Gabriela's main realm of interest is early childhood education.

realm of + noun phrase for field of interest

The discovery opened up a whole new realm of scientific possibilities.

Common collocations
  • realm of + subject (politics, science, art)
  • within the realm of
  • beyond the realm of
  • enter the realm of
  • the realm of possibility
Synonyms
  • field

    more everyday and neutral; the usual choice in professional contexts

  • domain

    more technical or formal, often suggests ownership or specialization

  • sphere

    more abstract, often referring to a broad social or intellectual arena

  • area

    the most general and least formal synonym

Grammar Patterns

the realm of + noun phrase

Usage Note

Frequently paired with 'of' to name the specific field (realm of politics, realm of science). The figurative sense appears in idiomatic expressions such as 'within/beyond the realm of possibility.'

Common Mistakes

The realm of mathematics are fascinating.
The realm of mathematics is fascinating.
'realm' is always singular; the phrase 'the realm of + plural noun' still takes a singular verb.

2. a nation whose supreme ruler is a monarch — a king, queen, or similar royal figu

2.nounB2
Definition

a nation whose supreme ruler is a monarch — a king, queen, or similar royal figure

Example

The queen's eldest son inherited the realm after her death.

inherited the realm

Trade agreements between the two realms strengthened the regional economy.

Common collocations
  • defend the realm
  • serve the realm
  • ruler of the realm
  • the entire realm
  • across the realm
Synonyms
  • kingdom

    more common and everyday; the neutral term for a monarch-ruled country

  • dominion

    more historical or formal; can imply broader territory under control

Grammar Patterns

the realm

a realm

Usage Note

Typically used in formal or literary contexts. Common in historical writing, fantasy literature, and constitutional references to monarchies. In everyday news about modern kingdoms, 'kingdom' is preferred over 'realm.'

Common Mistakes

France is a realm.' (when referring to a modern republic).
France is a republic, not a realm.
'realm' specifically means a country under a monarch; using it for any country is incorrect.
Idioms

Word family

  • realms
    nounB2

Synonym discussion

Sense: noun/1

While 'field', 'domain', 'sphere', 'area', and 'realm' all refer to a broad category of knowledge or activity, they differ in connotation and register. 'Field' is the most neutral and widely used in everyday and professional contexts ('field of medicine'). 'Domain' carries a slightly more technical or formal tone and often suggests a clearly bounded area of specialization ('the domain of statistics'). 'Sphere' is more abstract and tends to refer to a broad social or intellectual arena ('sphere of influence'). 'Area' is the most general and least formal, suitable for casual use ('area of interest'). 'Realm' is more dramatic and literary than the others; it implies a complete world or universe of activity rather than just a bounded category. For example: 'The discovery transformed the realm of particle physics' sounds more sweeping than 'the field of particle physics.'

field ↗domain ↗sphere ↗area ↗

Common collocations

Phrases

  • the realm of possibility
  • the realm of the dead
  • the realm of the living

Prepositions

Etymology

Old FrenchLatinEnglish

Realm comes from Old French 'realme' meaning 'kingdom,' which itself traces back to Latin 'regimen' ('rule' or 'government') and 'regalis' ('royal'). The original English meaning was a territory ruled by a monarch. By the 1500s, speakers began using it more broadly to describe any area of knowledge or activity — much like saying 'the kingdom of science' or 'the domain of art.'