Cherlin The Marriage-Go-Round analyzed the American pattern of frequent marriage, divorce and remarriage compared with other wealthy nations.
Arranged marriage is a marriage form in which the union is negotiated by parties other than the couple themselves, typically the families.
Bride kidnapping, or marriage by abduction, is a documented, and in most jurisdictions now criminalized, route into marriage historically practiced in parts of Central Asia and the Caucasus.
Source Wikipedia: Caste System in India
Charivari, the noisy communal mocking ritual of early modern Europe, was traditionally directed at marriages perceived to violate community norms, such as remarriage of widows or mismatched unions.
Child betrothal is a form of marriage arrangement made before the parties reach adulthood, historically documented across many agrarian and pastoralist societies.
A civil union offers many of the legal protections of marriage without using the marriage institution itself, typically created to extend recognition to couples excluded from marriage.
Source Wikipedia: Marriage
Common-law marriage is an informally constituted alternative to solemnized marriage, recognized in some jurisdictions after a period of cohabitation.
Concubinage has historically existed as a recognized institution alongside formal marriage in many legal traditions, granting a concubine and her children a defined, if lesser, status than a wife.
Cross-cousin marriage is a widely documented rule governing whom one may marry within the institution.
Source Wikipedia: Marriage
A property transfer practice attached to marriage validation, distinct from the marriage institution itself.
Rubin traffic in women essay theorized kinship and marriage systems as mechanisms that exchange women between men and thereby subordinate them.
Godparenthood, particularly the compadrazgo institution of Latin America, is frequently formalized through the same religious ceremony as marriage and functions to extend and reinforce kinship alliances between families.
Levirate marriage is a marriage-succession custom operating within the broader institution of marriage.
Source Wikipedia: Marriage
A rare variant form (4 of 1,231 surveyed societies) within the institution of marriage.
Source Wikipedia: Marriage
Polygamy is a marriage institution permitting a spouse to hold multiple concurrent marital partners, documented in both polygynous and, more rarely, polyandrous forms across many societies.
Ethnographic Atlas data records polygyny, occasional or frequent, as the most common marriage form among the 1,231 societies surveyed, a variant form within the institution of marriage rather than a separate institution.
Source Wikipedia: Marriage
Same-sex marriage extends the legal and social institution of marriage to couples of the same sex, now formally recognized in a growing number of jurisdictions worldwide.
Marriage is the socially and often legally recognized union that most societies treat as founding a family unit, though the two institutions are analytically distinct: marriage is the union, the family is the resulting kinship and residence group.