A free union is a romantic union between two or more persons without legal or religious recognition or regulation.
The term has been used since the late 19th century to describe a relationship into which all parties enter, remain, and depart freely. The free union is an alternative to, or rejection or criticism of marriage, viewing it as a form of slavery and human ownership, particularly for women. According to this concept, the free union of adults is a legitimate relationship that should be respected. A free union is made between two individuals, but each individual may have several unions of their own.