'stoplight' originates from the combination of 'stop' and 'light', where 'stop' meant 'to cease movement' and 'light' referred to 'a source of illumination'.

'stoplight' evolved from the early 20th-century term 'stop light', which was used to describe the newly invented traffic control devices.

Initially, it meant 'a light that signals vehicles to stop', and this meaning has largely remained the same in modern usage.