'stopcock' originates from Middle English, specifically the words 'stop' and 'cock,' where 'stop' meant 'to block' and 'cock' referred to a 'valve or spout.'

'stopcock' changed from the Middle English word 'stoppekok' and eventually became the modern English word 'stopcock'.

Initially, it meant 'a device to block or control flow,' and this meaning has largely remained the same in modern usage.