civil union

A civil union is a legally recognized union similar to marriage. Beginning with Denmark in 1989, civil unions under one name or another have been established by law in many developed countries in order to provide same-sex couples with rights, benefits, and responsibilities similar (in some countries, identical) rights and responsibilities to opposite-sex civil marriage. In some jurisdictions, such as Quebec, New Zealand, and Uruguay civil unions are also open to opposite-sex couples.
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Noun
1. a voluntary union for life (or until divorce) of adult parties of the same sex; "parties to a civil union have all the same benefits, protections, and responsibilities under Vermont law as spouses in a marriage"
(hypernym) marital status
(classification) law, jurisprudence