Per 《
新华词典》: traces to 《
仪礼·
丧服·
子夏传》 —
未嫁从父,
既嫁从夫,
夫死从子 ('unmarried, follow the father; married, follow the husband; widowed, follow the son'). The first half of the binomial
三从四德 (see that entry). Today almost always invoked critically — feminist historiography in China uses it as shorthand for the patriarchal ritual code.