- 哥 Ge: Older brother
- 弟 Di: Younger brother
- 姐 Jie: Older sister
- 妹 Mei: Younger sister
In usage, these words are usually repeated twice; e.g., 妹妹 Mei mei for one's younger sister. It is generally considered impolite to call an elder sibling by name. In larger families, 大哥 Da Ge or 大姐 Da Jie would refer to the eldest male or female child and others would be numbered (二哥 Er Ge, 三哥 San Ge, and so on). An elder brother is also sometimes referred to as 兄 Xiong, usually in the formula 兄弟 Xiongdi meaning "brothers" (in contrast to the Japanese 兄弟 Kyōdai, which can either mean "brothers" or "siblings", including sisters). Many people mistakenly thought brothers and sisters as a whole would be almost obsolete, however the one-child policy was obviously not meant to last very long (which otherwise would lead to eventual population decrease). For people born in 1980~2000s though, one-child family is dominant. Informally, it is not uncommon to call someone outside of your family by these names. Likewise, an elder sister can also be referred to as 姊 Zi, as in the formula 姊妹 Zimei(cognate with Japanese Shimai) meaning "sisters". When the two are combined, the term 兄弟姊妹 Xiongdizimei means "siblings".
Da Ge can also be used to address a non-related leader of an informal group, which happens overwhelmingly often in depictions of Chinese mafia bosses by Hong Kong films (the Cantonese Dai Lo is another term that gets thrown around quite frequently in these films). On that similar vein, Da Jie can be used to call said leader's wife, even if she is not, again, related by blood. This is comparable to the Japanese usage of 兄貴 Aniki, especially among (fictional) gangsters.
The youngest sibling older than you could be referred to as 小哥 Xiao Ge or 小姐 Xiao Jie, (小 Xiao = lit. "small") but that might not be as common as calling the youngest child 小弟 Xiao Di or 小妹 Xiao Mei. In any case, Xiao Jie is the Chinese equivalent of 'Miss' and used to address waitresses, retail clerks, etc. (And prostitutes, according to a few... interesting Chinese teachers. In fact, owing to this, Xiao Jie is an increasingly deprecated term in polite conversation, instead opting for the more appropriate 服務員 Fu Wu Yuan or "attendant") 妹妹 Mei Mei, using the same two words but a different inflection, can also be used to refer to an attractive young girl; this is generally considered to be an impolite and inappropriate term, but used quite often (and deliberately) among Chinese male adolescents (and beyond).
Cousins are also referred to by these four terms with the addition of 堂 tang or 表 biao according to arcane rules having to do with whether/how your fathers are related (basically if the cousins are on your mother's side of the family or their mother is your father's sister, 表 biao is used, if their father is your father's brother, 堂 tang is used). Contemporary people sometimes just don't bother the distinction of tang and biao(nothing to do with one-child policy here), using biao for all cousins. Though in Chinese-speaking countries outside of China proper(such as Singapore and Taiwan), be prepared to address your cousins with those mouthfuls. Alternatively, cousins may be informally addressed in the same manner as siblings.
Similarly, aunts and uncles are divided up by side of the family, but also whether they're related by blood or marriage and maybe birth order relative to your parent (usually to distinguish between your father's brothers; your mother's sisters get no such distinction). As such, there are 5 different terms for auntnote and 5 different terms for unclenote from all of the different combinations. Nieces and nephews too are referred to differently depending on whether their parent is your brother or your sister. Nephews are called either 姪子; zhi zi (brother's son) or 外甥 wai sheng (sister's son), while nieces are called either 姪女 zhi nü (brother's daughter) or 外甥女 wai sheng nü (sister's daughter).
There are at least five ways to refer to your parents. Each set is "father" and "mother", written in Traditional, then Simplified Chinese in parentheses (if there is a difference):
- 爸爸 Baba, 媽媽 (妈妈) Mama, or just 爸 Ba and 媽 (妈) Ma — standard terms
- 阿爸 Aba and 阿媽 (阿妈) Ama — Ba and Ma above combined with the familiar term of address 阿 A
- 老豆 Laodou and 老母 Laomu — a dialectal variation (e.g. it is used in Cantonese, pronounced Loudau and Loumou note )
- 爹 Die ("d'yeh", as opposed to the English word it resembles) and 娘 Niang — archaic terms, mostly heard in historical works
- 父親 (父亲) Fuqin and 母親 (母亲) Muqin (or collectively as 父母 Fumu) — formal terms mostly used to refer to someone else's parents.
- 父王 Fuwang and 母后 Muhou — terms used by royal families
(In modern pinyin, the Q stands for a slightly-more-sibilant ch phoneme, so Fuqin is "foo-chin", as opposed to the other English word it resembles.)
Grandparents are again divided by which side of the family they belong to and there are again multiple sets of words, some dependent on what part of China you're from. And grandchildren are also referred to differently depending on whether your son or daughter had them. And then once you get to aunts and uncles and great-aunts and great-uncles, depending on which side of the family they're from, or which side of which side of that family they're from, and whether they're older or younger than your direct relative in said family, you can pretty much stand by for Your Head A-Splode.