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.
union un·ion (yōōn'yən)
n.
The joining or amalgamation of two or more bodies.
The structural adhesion of the edges of a wound.
union (yn'yən) 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 United States; especially the northern states during the Civil War, which remained with the original United States government. (Compare Confederacy.)
1.
For example, (a, b, c) U (c, d, e) = (a, b, c, d, e)
2.
A union contrasts with a structure or record which stores values of all component types at once.
3.
(2002-02-26)