'twilight' originates from Middle English, specifically the word 'twi' meaning 'two' and 'light' meaning 'light', referring to the time of day when light is divided between day and night.

'twilight' changed from the Old English word 'twēonung' meaning 'doubt' or 'uncertainty' and eventually became the modern English word 'twilight'.

Initially, it meant 'the time of day when light is divided between day and night', and this meaning has largely remained the same in modern usage.