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do·main (dō-mān)
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n.
1. A territory over which rule or control is exercised.
2. A sphere of activity, influence, or knowledge: the domain of history. See Synonyms at field.
3. Mathematics
a. The set of all possible values of an independent variable of a function.
b. An open connected set that contains at least one point.
4. Computers A group of networked computers that share a common communications address.
5. Physics Any of numerous contiguous regions in a ferromagnetic material in which the direction of spontaneous magnetization is uniform and different from that in neighboring regions.
6. Biology Any of three primary divisions of organisms, consisting of the eukaryotes, bacteria, and archaea, that rank above a kingdom in taxonomic systems based on similarities of DNA sequences.
7. Law The land of one with paramount title and absolute ownership.

[French domaine, blend of Old French demaine (from Late Latin dominicum) and Latin dominium, property, both from dominus, lord; see dem- in the Appendix of Indo-European roots.]

The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
 

Indo-European & Semitic Roots Appendices

    Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:

    Indo-European Roots

    Semitic Roots

    The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.

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