noun
1. the act of making or becoming a single unit
e.g. the union of opposing factions
he looked forward to the unification of his family for the holidays
Synonym: unificationunitingconjugationjointure
2. the act of pairing a male and female for reproductive purposes
e.g. the casual couplings of adolescents
the mating of some species occurs only in the spring
Synonym: couplingmatingpairingconjugationsexual union
3. a device on a national flag emblematic of the union of two or more sovereignties (typically in the upper inner corner)
4. the occurrence of a uniting of separate parts
e.g. lightning produced an unusual union of the metals
5. a set containing all and only the members of two or more given sets
e.g. let C be the union of the sets A and B
Synonym: sumjoin
6. an organization of employees formed to bargain with the employer
e.g. you have to join the union in order to get a job
Synonym: labor uniontrade uniontrades unionbrotherhood
7. a political unit formed from previously independent people or organizations
e.g. the Soviet Union
8. healing process involving the growing together of the edges of a wound or the growing together of broken bones
Synonym: conglutination
9. the state of being a married couple voluntarily joined for life (or until divorce)
e.g. a long and happy marriage
God bless this union
Synonym: marriagematrimonyspousal relationshipwedlock
10. the state of being joined or united or linked
e.g. there is strength in union
Synonym: unification
adj
1. of trade unions
e.g. the union movement
union negotiations
a union-shop clause in the contract