something formed by uniting two or more things; combination.
a number of persons, states, etc., joined or associated together for some common purpose: student union; credit union.
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.
the United States: The Union defeated the Confederacy in 1865.
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.
the act of uniting or an instance of being united in marriage or sexual intercourse: an ideal union; an illicit union.
an organization of workers; a labor union.
Also calledjoin,logical sum,sum.the set consisting of elements each of which is in at least one of two or more given sets. Symbol: ∪
the least upper bound of two elements in a lattice.
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.
the junction or location at which the merging process has taken place.
any of various contrivances for connecting parts of machinery or the like.