BO

Chinese 薄: according to legend, some descendants of Shen Nong, a legendary emperor (2734–2697 bc), were granted an area named Bo in modern-day Shandong province, and adopted the place name as their surname. Additionally, an official of the state of Song during the Spring and Autumn period (722–481 bc) was granted a town named Bo in modern-day Henan province, and his descendants also adopted the place name as their surname. The character also means ‘thin’ or ‘slim’, and ‘weak’.

Chinese 伯: from the name of Bo Yi, a famous adviser to the model emperors Shun and Yao around 2200 BC. This character also means ‘oldest brother’, and is often used as a personal name with this sense.

Vietnamese: unexplained.

Other Southeast Asian: unexplained.