Nuclear family is the smallest. It is also called the primary family. In a nuclear family, there are the parents and their children. It consists of members belonging to two generations. An Extended family is quite different. It is commonly known as joint family. There are different types of extended families. In an extended family, more than one couple and their children live. This can be a group of brothers and their families. It could be the family of an old couple whose children and grandchildren stay with them. An extended family is often seen as a sign of India. But that was never a strong-knit family. It was limited to some regions and some communities. An extended family is not a strong form even now.