Final answer:
The term referring to the practice of marrying within one's own social or cultural group is Endogamy.
Step-by-step explanation:
The term that refers to the practice of marrying a person in the group in which one belongs is known as Endogamy. Marrying within one's own social background is a common occurrence due to cultural norms and expectations. However, unlike endogamous unions, people also have the option to engage in exogamous marriages, which are unions between spouses from different social categories, where decisions may be based more on love and compatibility than on social standing or economics.