A civil union is a legally recognized relationship between members of a same-sex couple, with rights similar to those of a marriage relationship.
As of my knowledge cutoff in early 2023, North Dakota does not recognize civil unions. The state only recognizes marriage, which is defined as a legal union between two people regardless of gender, following the U.S. Supreme Court's decision in Obergefell v. Hodges (2015) that legalized same-sex marriage nationwide. This decision requires all states to license and recognize marriages between same-sex couples on the same terms and conditions as marriages between opposite-sex couples. Therefore, in North Dakota, same-sex couples have the option to marry and receive the same state and federal benefits, protections, and responsibilities that are conferred to opposite-sex married couples, but there is no separate legal status of civil unions available.