Hypergamy (colloquially referred to as "marrying up") is a term used in social science for the act or practice of a person marrying a spouse of higher caste or social status than themselves. It is mostly practiced by women.
The antonym "hypogamy" refers to the inverse: marrying a person of lower social class or status (colloquially "marrying down"). Both terms were coined in the Indian subcontinent in the 19th century while translating classical Hindu law books, which used the Sanskrit terms anuloma and pratiloma, respectively, for the two concepts.
The term hypergyny is used to describe the overall practice of women marrying up, since the men would be marrying down.