bù
no
Original meaning:
sepal
Pictograph of sepals of a flower. The modern meaning "no" is a phonetic loan.
Evolution

Oracle script
(~1250-1000 BC)
Bronze script
Early Western Zhou (~1000 BC)
Seal script
Shuowen (~100 AD)
Clerical script
Eastern Han dynasty (25-220 AD)Regular script
ModernDefinitions
Component uses
Sources