Build a relationship step by step, such as father's, then elder brother's, then son, and there are 1,195,740 of them within six steps, counting a male and a female speaker and leaving out same-sex marriages, which the traditional terms do not cover. About 53% end at one standard Chinese term. About 20% could be any of several people who are called different things. And about 26% have no single word at all and are described instead.
For the most common relatives, the terms are settled. Your father's elder brother is 伯父 and his younger brother 叔父; their wives are 伯母 and 嬸嬸 (婶婶). Your father's sisters are 姑媽 (姑妈), your mother's sisters 姨媽 (姨妈), and your mother's brother's wife is 舅媽 (舅妈). A cousin through your father's brothers is 堂, and every other cousin, through your father's sisters or your mother's side, is 表. Those definitions are from Taiwan's Ministry of Education dictionaries; the standard mainland dictionary is not online, so we give no mainland-specific rulings.
弟弟 depends on who was born first
We got those shares by running every relationship through the rules behind our Chinese kinship calculator. The 20% with several answers are mostly questions of birth order. For a man, 爸爸的兒子, his father's son, is himself, an elder brother (哥哥) or a younger brother (弟弟). 爺爺的兒子, his grandfather's son, is his father, 伯伯 or 叔叔. His father's son's wife is his own wife, 嫂子 or 弟妹.
Until September 2026 the calculator did not say so. It treated every such tie as "younger", so father's son came out 弟弟 in both directions, two people each calling the other younger brother. It now lists every reading, and 24 of the 162 two-step relationships have more than one.
岳父 is a word for talking about him
Many of the answers are terms for referring to a relative, not for addressing them. Taiwan's Ministry of Education dictionary of Taiwanese Hokkien says it outright in its entry for 大官 (ta-kuann), a woman's husband's father: the word is "用於背稱及描述，面稱時則與丈夫一致", used when speaking of him, while to his face she calls him what her husband does. The same dictionary gives 大家 (ta-ke) for the husband's mother, again as a word for speaking about her. That is one entry about one relative, so we would not make it a rule, but it is a reason not to assume that 岳父, a man's word for his wife's father, is what he says to him.
The in-law words people meet most are also dictionary headwords. 親家 (亲家) is what the two sets of parents in a marriage call each other; 連襟 (连襟) is what the husbands of two sisters call each other; 妯娌 names the relationship between the wives of two brothers. In Singapore and Malaysia many families use home forms such as Ah Ma and Ah Kong. No dictionary we could open records them, and the Hokkien given here is Taiwan's, which may not match Singapore or Penang usage; our guide to Chinese ancestry in Southeast Asia covers the dialect groups behind them.
姑婆 is defined differently in the ministry's own dictionaries
Taiwan's Ministry of Education publishes two general dictionaries, and they do not agree on 姑婆. The concise dictionary defines it as the sister of your father's father or your mother's father. The revised dictionary, which we read through a public mirror of its text, gives the sister of your father's father and, separately, a husband's father's sister, and does not mention your mother's father. The calculator now follows the concise definition.
The long ladder of ancestors that circulates online, climbing through 天祖 and 烈祖 to 鼻祖, fares worse. The 爾雅 (尔雅), a classical Chinese glossary with a chapter on relatives, stops at 高祖, the great-great-grandfather, and the concise dictionary has no entry for 天祖 and gives 鼻祖 only as "founder". Going down, the 爾雅 names seven generations of descendants, ending at 雲孫. 耳孫 is not among them; it appears in the Han dynastic history, and the revised dictionary counts it as the eighth generation.
姨 once meant a wife's sister
The 爾雅 also shows how far the words have moved. In its chapter on relatives, a mother's sisters are 從母, and 姨 is the word for a wife's sisters. 姪 is a woman's word for her brother's children. A man calls his wife's parents 外舅 and 外姑. And a woman calls her husband's father and mother 舅 and 姑, the words that name a mother's brother and a father's sister today.
