| Yoo, Yu or Ryu | |
| Hangul | 유 or 류 |
|---|---|
| Hanja | |
| Revised Romanization | Yu or Ryu |
| McCune–Reischauer | Yu or Ryu |
Yoo or Yu, or sometimes Ryu or Ryoo, is the English transcription of several Korean surnames written as 유 or 류 in hangul. As of 2000, roughly a million people are surnamed Yoo in South Korea, making up approximately 2% of the population. Of those, the most common is Ryu (Hanja: 柳, Hangul: 류),[1] with more than six hundred thousand holders, whereas Yoo (Hanja: 兪, 余 Hangul: 유) accounts for about one hundred thousand.
The family name Yoo can be represented by any of the four hanja: 柳 (류), 劉, 兪 and 庾, each with a different meaning. In Korean, the characters 劉 and 柳 refer to 유 (Yoo) or 류 (Ryu) and are spelled as such because of the first initial sound rule (두음 법칙) in Korean, whereas the characters 兪 and 庾 refer only to 유 (Yoo). Some of these characters are used to write the Chinese surnames Liu (劉 or 柳) and Yu (兪，余).
Notable 柳 (Ryu) clans include the Munhwa Ryu clan and the Pungsan Ryu.