lǜ, shuài
rate, frequency
Original meaning:
rope
Pictograph of a rope with four dots representing bits of threads. Based on the original meaning "rope". The meaning later shifted to "lead", "follow", "standard", "rate", and "frequency".
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
Sources