What term is used to describe people treated like family members but are not blood relatives?

The term used to describe people treated like family members but who are not blood relatives is "fictive kin." This concept refers to relationships that function like familial connections despite the absence of biological ties. Fictive kin can include close friends, mentors, or community members who provide emotional support, social bonds, and a sense of belonging similar to that which one might receive from family members.

This concept is particularly relevant in various social contexts where individuals may form significant relationships that fulfill familial roles, especially in communities where traditional family structures may be absent or where chosen family plays a crucial role in an individual's life. In essence, fictive kinship highlights the importance of social and emotional ties that transcend genetics, thereby emphasizing the flexibility of what constitutes a family.