Hypergamy

Practice of a person marrying a spouse of higher social status

In social science, hypergamy (colloquially referred to as marrying up or dating up) originally referred to marrying or dating someone of higher socioeconomic class; today more commonly (especially colloquially and in evolutionary psychology) however, it refers to partnering with someone of higher general/composite mate value. The antonym hypogamy refers to the inverse, a preference for dating or marrying someone of lower mate value or socioeconomic class. The term hypergyny can also be used to describe the practice of women marrying up.

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