Union generally means an organization formed to conduct an activity. Depending on its context, it can have several other meanings.

Organization

• Trade union, a workers' organization (called a "labor union" in American English)
• Credit union, a co-operative financial institution
• Personal union, separate, independent states that share the same monarch
• Political union, a type of state composed of smaller states
• Poor Law union, a group of parishes providing relief (United Kingdom, 16th century - 20th century)
• Rugby union, a type of rugby football
• Civil union, a commitment ceremony similar to marriage
• Students' union, an organization on many university campuses which organizes students.

Political

• African Union, an inter-governmental organization in Africa.
• Government of India, officially the Union Government.
• European Union, an inter-governmental organization in Europe.
• Political union, the state of unification between two or more states
• Union (American Civil War), the northern states that did not secede.
• United States Republican Party, known as the Union Party during the 1864 election.
• The Union (l'Unione), the Italian coalition that won the April 2006 general elections