Short answers, pulled from the story.
The word marriage appeared in English around 1300, borrowed from the Old French mariage of the 12th century, which traces to the Latin maritatus, meaning married. The related word matrimony comes from the Latin matrimonium, derived from mater, the word for mother.
Marriage takes several forms by number of spouses. Of 1,231 societies in the Ethnographic Atlas, 186 were monogamous, 453 had occasional polygyny, 588 had frequent polygyny, and 4 practiced polyandry. Group marriage was found in only the Kaingang of Brazil among 250 societies George Murdock reported in 1949.
A dowry transfers parental property to a daughter at her marriage to support her in widowhood. Bridewealth flows the opposite way, paid by the groom or his family to the bride's parents. The mahr is the woman's portion of the groom's wealth in Islamic tradition, set high in places like Iran, where it can exceed one million US dollars.
The United States Supreme Court ruled unanimously in 1967 in Loving v. Virginia that anti-miscegenation laws were unconstitutional. The ruling ended such laws in the 16 states that still enforced them. From 1913 until 1948-30 of the then 48 states had enforced these bans.
Child marriage, where one or both spouses are under 18, is most common in rural sub-Saharan Africa and South Asia, with Niger reporting the highest rate at 75 percent. In 1880 in the United States the minimum age of consent ranged from 7 to 12, and as of 2017 over half of the 50 states had no explicit minimum marriage age.
Critics have compared marriage to prostitution and patriarchy. Mary Wollstonecraft called it legal prostitution in the 18th century, and Bertrand Russell wrote in Marriage and Morals that women endure more undesired sex in marriage than in prostitution. Historically married women were treated as the property of their husbands under doctrines such as coverture.