stem family

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A family system in which the a couple's firstborn lives with them in the family home and whose spouse moves into the home of the said in-laws and the younger couple's children are raised in the home of the grandparents. Usually the younger offspring of move out upon marriage. The inheritance, depending on the culture, may or may not be the most favorable to the firstborn.