interval

The word 'interval' originates from the Latin intervallum, a compound of inter- ("between") and vallum ("rampart, wall"). In its original military context, it literally meant the space between two ramparts or defensive walls of a camp. This concrete sense of a physical gap was later abstracted in Latin to denote any intervening space or distance. By the time it entered Middle English via Old French intervalle, it had already acquired its dual modern meanings: a spatial gap and, through further metaphorical extension, a period of time between events, conceptualizing time as a linear space with measurable distances.

Structure: inter (between) + val (rampart, wall) - inter: From Latin inter, meaning "between, among". A preposition/adverb in Latin, used as a prefix in English. - val: From Latin vallum, meaning "rampart, wall, defensive earthwork". A noun in Latin, here used in a compound form.