Multigenerational living means three generations under one roof. This is typically your parent, you and your child or you, your child and your grandchildren. Sometimes one generation moves in with the other two and makes do; some builders offer two master suites.
Issues to Consider
Do the economics make sense? Pooling money goes further and there’s no need for institutional care. Each generation is getting quality (and certainly quantity!) time with the other. It might mean built in childcare or eldercare. But it could also mean family friction, less privacy and personal time. Make sure everyone has the same expectations and that you regularly discuss and fine-tune the arrangement.