'creatinine' originates from French, specifically the word 'créatinine,' where 'créatine' came from Greek 'kreas' meaning 'flesh,' and the suffix '-ine' denoted 'a chemical substance.'

'créatinine' transformed into the German word 'Kreatinin,' and eventually became the modern English word 'creatinine'.

Initially, it meant 'a compound derived from creatine found in urine,' and this meaning has largely remained the same in modern usage.