'interval' originates from Latin, specifically the word 'intervallum,' where 'inter-' meant 'between' and 'vallum' referred to a 'rampart' or 'wall' (hence a space or gap).

'interval' changed from Medieval Latin 'intervallum' (and via Old French 'intervalle') and entered Middle English as 'interval', eventually becoming the modern English word 'interval'.

Initially it meant 'a space between ramparts or walls,' but over time it broadened to mean any space or period between two points or events (time, physical space, musical pitch, mathematical range).