(yn′yən) noun
1. The act of uniting, or the state of being united; a joining; coalescence; junction.
2. That which is constituted as one by the combination of elements previously separate; a coalition; confederation; league.
3. A combination of co–laborers for the joint and mutual protection of their common interests. See TRADE UNION.
4. Brit. An amalgamation of parishes for administration of poor relief; also, a workhouse administered by such a union.
5. Agreement in sentiment or action; harmony; concord; unanimity.
6. The joining of two persons in marriage, or the resulting state of wedlock.
7. A device emblematic of union borne in the canton of a flag, as the three crosses in a British ensign; the canton itself containing such device, sometimes used separately as a flag, as the blue canton with white stars in the flag of the United States, and the Union Jack of Great Britain.
8. A coupling or connection for pipes or rods.
9. A fabric made of two or more materials, as cotton and wool.
10. Obs. A pearl of extraordinary worth.
—adjective Of, pertaining to, or adhering to a union, particularly a political or trade union. [<F <LL unio, -onis <L unus one. Doublet of ONION.] Synonyms (noun): coalition, combination, conjunction, junction, juncture, oneness, unification, unity. Unity is oneness, the state of existing as essentially one, especially of that which never has been divided or of that which cannot be conceived of as resolved into parts; as, the unity of the human soul. Union is a bringing together of things that have been distinct, so that they combine or coalesce to form a new whole, or the state or condition of things thus brought together; in a union the separate individuality of the things united is never lost sight of; we speak of the union of the parts of a fractured bone. ALLIANCE, ASSOCIATION, ATTACHMENT, HARMONY, MARRIAGE. Antonyms: analysis, contrariety, decomposition, disconnection, disjunction, dissociation, disunion, division, divorce, separation, severance.
PIPE UNION

(yn′yən) noun
1. The United States regarded as a national unit: with the.
2. The Union of South Africa.
—adjective Of, pertaining to, or loyal to the United States, especially the Federal government during the Civil War: a Union soldier; He was Union to the core.