Courtesy name (Zi)
Chinese name
Traditional Chinese	(表) 字
Hanyu Pinyin	(biǎo) zì
Wade–Giles	(piao)-tzu
Vietnamese name
Vietnamese alphabet	biểu tự tên tự tên chữ
Chữ Hán	表字
Chữ Nôm	𠸜字 𠸜𡨸
Korean name
Hangul	자
Hanja	字
Revised Romanization	ja
McCune–Reischauer	cha
Japanese name
Kanji	字
Hiragana	あざな
Revised Hepburn	azana

A courtesy name (Chinese: 字; pinyin: zì; lit. 'character'), also known as a style name, is an additional name bestowed upon individuals at adulthood, complementing their given name.^[1] This tradition is prevalent in the East Asian cultural sphere, particularly in China, Japan, Korea, and Vietnam.^[2] Courtesy names are a marker of adulthood and were historically given to men at the age of 20, and sometimes to women upon marriage.

Unlike art names, which are more akin to pseudonyms or pen names, courtesy names served a formal and respectful purpose.^[1] In traditional Chinese society, using someone’s given name in adulthood was considered disrespectful among peers, making courtesy names essential for formal communication and writing.

Courtesy names often reflect the meaning of the given name or use homophonic characters, and were typically disyllabic after the Qin dynasty. The practice also extended to other East Asian cultures, and was sometimes adopted by Mongols and Manchus during the Qing dynasty. The choice of a courtesy name was significant, intended to express moral integrity and respect within the cultural context.

A courtesy name is a name traditionally given to Chinese men at the age of 20 sui, marking their coming of age. It was sometimes given to women, usually upon marriage.^[1] The practice is no longer common in modern Chinese society. According to the Book of Rites, after a man reached adulthood, it was disrespectful for others of the same generation to address him by his given name.^[3] Thus, the given name was reserved for oneself and one's elders, whereas the courtesy name would be used by adults of the same generation to refer to one another on formal occasions or in writing. Another translation of zi is "style name", but this translation has been criticised as misleading, because it could imply an official or legal title.^[1]

Generally speaking, courtesy names before the Qin dynasty were one syllable, and from the Qin to the 20th century they were mostly disyllabic, consisting of two Chinese characters.^[1] Courtesy names were often relative to the meaning of the person's given name, the relationship could be synonyms, relative affairs, or rarely but sometimes antonym. For example, Chiang Kai-shek's given name (中正, romanized as Chung-cheng) and courtesy name (介石, romanized as Kai-shek) are both from the yù (豫) hexagram 16 of I Ching.^[4]

Another way to form a courtesy name is to use the homophonic character zi (子) – a respectful title for a man – as the first character of the disyllabic courtesy name. Thus, for example, Gongsun Qiao's courtesy name was Zichan (子產), and Du Fu's was Zimei (子美). It was also common to construct a courtesy name by using as the first character one which expresses the bearer's birth order among male siblings in his family. Thus Confucius, whose name was Kong Qiu (孔丘), was given the courtesy name Zhongni (仲尼), where the first character zhong indicates that he was the second son born into his family. The characters commonly used are bo (伯) for the first, zhong (仲) for the second, shu (叔) for the third, and ji (季) typically for the youngest, if the family consists of more than three sons. General Sun Jian's four sons, for instance, were Sun Ce (伯符, Bófú), Sun Quan (仲謀, Zhòngmóu), Sun Yi (叔弼, Shūbì) and Sun Kuang (季佐, Jìzuǒ).^[5]

Reflecting a general cultural tendency to regard names as significant, the choice of what name to bestow upon one's children was considered very important in traditional China.^[6] Yan Zhitui of the Northern Qi dynasty asserted that whereas the purpose of a given name was to distinguish one person from another, a courtesy name should express the bearer's moral integrity.^{[citation needed]}

Prior to the twentieth century, sinicized Koreans, Vietnamese, and Japanese were also referred to by their courtesy name. The practice was also adopted by some Mongols and Manchus after the Qing conquest of China.^{[citation needed]}

• Cognomen, the third name of a citizen of ancient Rome