domain

Meanings

1. 1nouncountable

   A particular area of knowledge, activity or interest.

   Grammar: Usually with of or a describing word: the domain of medicine, the public domain.

   Patterns

   • the domain of something
   • within someone's domain

   Cooking is her domain, so I stay out of the kitchen.

   Climate science is a large domain with many sub-fields.

   These questions fall outside my domain.

2. 2nouncountablecomputing

   The website address that identifies a site on the internet, such as the part ending in .com.

   Grammar: Often used with name: a domain name.

   Patterns

   • register a domain
   • a domain name

   We registered the domain for our bakery yesterday.

   Her domain expires next month.

   The email domain is the part after the @ sign.

3. 3nouncountableformal

   A territory controlled by one ruler or government.

   Grammar: Often used in history or in jokes about a person's own territory.

   Patterns

   • rule a domain
   • a king's domain

   The king's domain stretched from the river to the mountains.

   The attic is the cat's domain.

   Few travelers entered the duke's domain.

4. 4nouncountablemathematics

   In mathematics, the set of all input values for which a function is defined.

   Grammar: Contrast with range, the set of output values.

   Patterns

   • the domain of a function

   The domain of this function is all positive numbers.

   Check that your input lies in the domain.

   The teacher asked us to state the domain and the range.

Word forms

Common combinations

the public domain

The novel is now in the public domain.

domain name

Choose a short domain name.

domain expert

We hired a domain expert in finance.

outside your domain

That question is outside my domain.

domain of knowledge

Each domain of knowledge has its own vocabulary.

Synonyms and how they differ

field

Field is the most common word for an area of study or work, and is less often used for control of territory.

sphere

Sphere suggests an area of influence or activity and is more figurative than domain.

realm

Realm is more literary, often used for kingdoms or imagined worlds.

territory

Territory emphasizes land or ground that belongs to someone, so it is less abstract than domain.

Word family

domainial adjective

a rare adjective relating to an estate or domain

dominion noun

rule or control over a territory

dominate verb

to have control or the most influence

domestic adjective

relating to the home, from a related Latin root

Commonly confused: domain or dominion?

Practice

Make it your own

Write a sentence using “domain”, then check it and compare it with the examples above.

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