In history this was the name of the eldest son and heir apparent of Qin Shi Huang (秦始皇), the first emperor of the Qin Dynasty (221 - 206 BCE). He protested against his father’s infamous burning of books and burying of scholars, arguing that it would further destabilize the newly-unified country, but he was exiled from court and later forced to commit suicide. Fusu is remembered as a virtuous but ill-fated prince, and is sometimes worshipped in China today as a Door God.
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In modern China, this name is considered to be a cute/pet name and is strongly associated with children, cartoon characters and animals.