'catheter' originates from Greek, specifically the word 'kathetēr', where 'kathe-' (from 'kathíēnai') meant 'to let down' or 'to put down'.

'catheter' changed from the Greek word 'kathetēr' into Late Latin 'catheter', passed into Medieval/Modern Latin and French, and eventually became the modern English word 'catheter'.

Initially, it referred to an instrument 'for letting down' or inserting; over time it came to mean the specific medical tube used to drain or introduce fluids into the body.