domain

UK: /dəʊˈmeɪn/ US: /doʊˈmeɪn/ ,(dō mān′)

WordReference Random House Learner's Dictionary of American English © 2025

do•main /doʊˈmeɪn/   n. [countable]

1. a field or area of thought, etc;
   subject;
   area of interest:
   He works in the domain of public health.
2. Government the territory governed by a ruler or government:
   The domains stretched for hundreds of miles in every direction.

WordReference Random House Unabridged Dictionary of American English © 2025

do•main  (dō mān′), n. 

1. a field of action, thought, influence, etc.:
   the domain of science.
2. Government the territory governed by a single ruler or government;
   realm.
3. a realm or range of personal knowledge, responsibility, etc.
4. a region characterized by a specific feature, type of growth or wildlife, etc.:
   We entered the domain of the pine trees.
5. Law land to which there is superior title and absolute ownership.
6. Mathematics
   • the set of values assigned to the independent variables of a function.
   • Mathematics region (def. 11a).
7. [Physics.] one of many regions of magnetic polarity within a ferromagnetic body, each consisting of a number of atoms having a common polarity, and collectively determining the magnetic properties of the body by their arrangement.
8. Crystallography a connected region with uniform polarization in a twinned ferroelectric crystal.

• Late Latin dominicum, noun, nominal use of neuter of Latin dominicus of a master, equivalent. to domin(us) lord + -icus -ic
• French domaine, alteration, by association with Latin dominium dominium, of Old French demeine
• 1595–1605

do•ma′ni•al, adj. 

domain, +n. [Computers.]

1. a group of computers and devices on a network that are administered under the same protocol.
2. the top level in a domain name, indicating the type of organization or geographical location and officially designated in the suffix, as.com for commercial enterprises in the U.S.

Collins Concise English Dictionary © HarperCollins Publishers::

domain / dəˈmeɪn/ noun

1. land governed by a ruler or government
2. land owned by one person or family
3. a field or scope of knowledge or activity
4. a region having specific characteristics or containing certain types of plants or animals
5. a park or recreation reserve maintained by a public authority, often the government
6. the absolute ownership and right to dispose of land
   See also demesne, eminent domain
7. the set of values of the independent variable of a function for which the functional value exists
   Compare range8a
8. another term for universe of discourse: domain of quantification
9. range of significance (esp in the phrase domain of definition)
10. Also called: magnetic domain one of the regions in a ferromagnetic solid in which all the atoms have their magnetic moments aligned in the same direction
11. a group of computers, functioning and administered as a unit, that are identified by sharing the same domain name on the internet
12. Also called: superkingdom the highest level of classification of living organisms. Three domains are recognized: Archaea (see archaean), Bacteria (see bacteria), and Eukarya (see eukaryote)
13. a structurally compact portion of a protein molecule

Etymology: 17th Century: from French domaine, from Latin dominium property, from dominus lord