n.

1. an organization of employees formed to bargain with the employer;
   labor union, trade union, trades union, brotherhood
   
   • you have to join the union in order to get a job
2. the United States (especially the northern states during the American Civil War);
   Union, North
   
   • he has visited every state in the Union
   • Lee hoped to detach Maryland from the Union
   • the North's superior resources turned the scale
3. the act of pairing a male and female for reproductive purposes;
   coupling, mating, pairing, conjugation, sexual union
   
   • the casual couplings of adolescents
   • the mating of some species occurs only in the spring
4. the state of being joined or united or linked;
   unification
   
   • there is strength in union
5. the state of being a married couple voluntarily joined for life (or until divorce);
   marriage, matrimony, spousal relationship, wedlock
   
   • a long and happy marriage
   • God bless this union
6. healing process involving the growing together of the edges of a wound or the growing together of broken bones;
   conglutination
7. a political unit formed from previously independent people or organizations
   
   • the Soviet Union
8. a set containing all and only the members of two or more given sets;
   sum, join
   
   • let C be the union of the sets A and B
9. the occurrence of a uniting of separate parts
   
   • lightning produced an unusual union of the metals
10. a device on a national flag emblematic of the union of two or more sovereignties (typically in the upper inner corner)
11. the act of making or becoming a single unit;
    unification, uniting, conjugation, jointure
    
    • the union of opposing factions
    • he looked forward to the unification of his family for the holidays

adj.

1. being of or having to do with the northern United States and those loyal to the Union during the American Civil War;
   Union, Federal
   
   • Union soldiers
   • Federal forces
   • a Federal infantryman
2. of trade unions
   
   • the union movement
   • union negotiations
   • a union-shop clause in the contract