Step 1: Define endogamy.
Endogamous marriage is a marriage rule that requires a person to marry within their own defined social group, such as their own caste, sub-caste, religion, or community.
Step 2: Give the purpose and example.
This rule is meant to keep the group's identity, property, and status inside the group itself. In India, most caste based marriages follow endogamy, where a person from one caste is expected to marry another person from the same caste.
Final Answer:
Endogamous marriage means marrying strictly within one's own caste or community group.