'notochord' originates from Greek, specifically the word 'nōton' meaning 'back' and 'chordē' meaning 'string'.

'nōton' and 'chordē' combined to form the Greek word 'notochordos', which eventually became the modern English word 'notochord'.

Initially, it meant 'back string', referring to its function in the body, and this meaning has largely remained the same in modern usage.