Definition of domain
1 law a : complete and absolute (see absolute 3) ownership of land <our highways and roads have been in the domain of state and local governments — T. H. White b. 1915> — compare eminent domainb : land so owned
2 : a territory over which dominion (see dominion 2) is exercised <The forest is part of the king's domain.>
3 : a region distinctively marked by some physical feature <a domain of rushing streams, tall trees, and lakes>
4 : a sphere (see sphere 4b) of knowledge, influence, or activity <the domain of biblical scholarship> <outside the domain of city police>
6 physics : any of the small randomly oriented regions of uniform magnetization in a ferromagnetic substance
7 mathematics : integral domain
8 biology : the highest taxonomic category in biological classification ranking above the kingdom (see kingdom 5b)
Examples of domain in a sentence
The forest is part of the king's domain.
My sister is the math expert in the family, but literature is my domain.
Childcare is no longer solely a female domain.
Origin and Etymology of domain
alteration of Middle English demayne, from Anglo-French demeine, from Latin dominium, from dominus —see dominate
First Known Use: 15th century
DOMAIN Defined for English Language Learners
Definition of domain for English Language Learners
: the land that a ruler or a government controls
: an area of knowledge or activity
computers : a section of the Internet that is made up of computers or sites that are related in some way (such as by use or source)
DOMAIN Defined for Kids
Word Root of domain
The Latin word dominus, meaning “master,” gives us the root domin. Words from the Latin dominus have something to do with being another's master. To dominate is to have power and control over as if being someone's master. A domain, or land under the control of a government, is a land with a particular master or ruler. Dominion is controlling power, similar to the power of a master over others.
Medical Definition of domain
1: any of the three-dimensional subunits of a protein that together make up its tertiary structure, that are formed by folding its linear peptide chain, and that are variously considered to be the basic units of protein structure, function, and evolution <immunoglobulin light chains have two domains and heavy chains have four or five domains, depending on class—Journal of the American Medical Association>
2: the highest taxonomic category in biological classification ranking above the kingdom
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