adopt
To legally take in and care for as family.
To adopt means to legally take someone else's child into your family and raise them as your own. When parents adopt a child, that child becomes a full member of their family with all the same rights and love as any other child. Families adopt for many reasons: some parents cannot have biological children, some want to give a home to a child who needs one, and some simply want to expand their family through adoption.
The word also means to take something up and start using it as your own. A school might adopt a new math curriculum, meaning they decide to use it instead of their old one. A community might adopt a highway, agreeing to keep that stretch of road clean. When you adopt a new habit, you make it part of your regular routine. If your family adopts a tradition from another culture, like celebrating Lunar New Year, you're making it part of your own life.
You might also hear about people who adopt pets from animal shelters, giving homeless dogs or cats a permanent home. The word carries a sense of commitment and care: when you adopt someone or something, you're taking responsibility and making it genuinely yours.