See more synonyms for union on Thesaurus.com
  1. the act of uniting two or more things.
  2. the state of being united.
  3. something formed by uniting two or more things; combination.
  4. a number of persons, states, etc., joined or associated together for some common purpose: student union; credit union.
  5. a group of states or nations united into one political body, as that of the American colonies at the time of the Revolution, that of England and Scotland in 1707, or that of Great Britain and Ireland in 1801.
  6. the Union. the United States: The Union defeated the Confederacy in 1865.
  7. a device emblematic of union, used in a flag or ensign, sometimes occupying the upper corner next to the staff or occupying the entire field.
  8. the act of uniting or an instance of being united in marriage or sexual intercourse: an ideal union; an illicit union.
  9. an organization of workers; a labor union.
  10. Mathematics.
    1. Also called join, logical sum, sum.the set consisting of elements each of which is in at least one of two or more given sets. Symbol: ∪
    2. the least upper bound of two elements in a lattice.
  11. the process or result of merging or integration of disjoined, severed, or fractured elements, as the healing of a wound or broken bone, the growing together of the parts in a plant graft, the fusion of pieces in a welding process, or the like.
  12. the junction or location at which the merging process has taken place.
  13. any of various contrivances for connecting parts of machinery or the like.
  14. Textiles.
    1. a fabric of two kinds of yarn.
    2. a yarn of two or more fibers.

Origin of union

1400–50; late Middle English < Middle French < Late Latin ūniōn- (stem of ūniō), equivalent to Latin ūn(us) one + -iōn- -ion
Related formsin·ter·un·ion, noun, adjectivemis·un·ion, nounpre·un·ion, adjectivepro·un·ion, adjectiveself-un·ion, noun

Synonyms for union

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Synonym study

1. Union, unity agree in referring to a oneness, either created by putting together, or by being undivided. A union is a state of being united, a combination, as the result of joining two or more things into one: to promote the union between two families; the Union of England and Scotland. Unity is the state or inherent quality of being one, single, individual, and indivisible (often as a consequence of union): to find unity in diversity; to give unity to a work of art. 5. See alliance.

Antonyms for union


[yoon-yuh n]
  1. a township in NE New Jersey.
  2. a city in NW South Carolina.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

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British Dictionary definitions for union


  1. the condition of being united, the act of uniting, or a conjunction formed by such an act
  2. an association, alliance, or confederation of individuals or groups for a common purpose, esp political
  3. agreement or harmony
  4. short for trade union
  5. the act or state of marriage or sexual intercourse
  6. a device on a flag representing union, such as another flag depicted in the top left corner
  7. a device for coupling or linking parts, such as pipes
  8. (often capital)
    1. an association of students at a university or college formed to look after the students' interests, provide facilities for recreation, etc
    2. the building or buildings housing the facilities of such an organization
  9. Also called: join maths a set containing all members of two given sets. Symbol: ⋃, as in A⋃B
  10. (in 19th-century England)
    1. a number of parishes united for the administration of poor relief
    2. a workhouse supported by such a combination
  11. textiles a piece of cloth or fabric consisting of two different kinds of yarn
  12. (modifier) of or related to a union, esp a trade union

Word Origin for union

C15: from Church Latin ūniō oneness, from Latin ūnus one


noun the Union
  1. British
    1. the union of England and Wales from 1543
    2. the union of the English and Scottish crowns (1603–1707)
    3. the union of England and Scotland from 1707
    4. the political union of Great Britain and Ireland (1801–1920)
    5. the union of Great Britain and Northern Ireland from 1920
  2. US
    1. the United States of America
    2. the northern states of the US during the Civil War
    3. (as modifier)Union supporters
  3. short for the Union of South Africa
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for union

early 15c., "action of joining one thing to another," from Old French union (12c.), from Late Latin unionem (nominative unio) "oneness, unity, a uniting," also in Latin meaning "a single pearl or onion," from unus "one," from PIE *oinos (see one).

Sense of "action of uniting into one political body" is attested from 1540s. Meaning "group of people or states" is from 1650s. Short for trade union, it is recorded from 1833. U.S. political sense is attested from 1775; used especially during the Civil War, in reference to the remainder of the United States after the Southern secession.

Online Etymology Dictionary, © 2010 Douglas Harper

union in Medicine


  1. The joining or amalgamation of two or more bodies.
  2. The structural adhesion of the edges of a wound.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

union in Science


  1. A set whose members belong to at least one of a group of two or more given sets. The union of the sets {1,2,3} and {3,4,5} is the set {1,2,3,4,5}, and the union of the sets {6,7} and {11,12,13} is the set {6,7,11,12,13}. The symbol for union is . Compare intersection.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

union in Culture


The United States; especially the northern states during the Civil War, which remained with the original United States government. (Compare Confederacy.)

The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.