'instantaneously-finished' originates from the combination of 'instantaneous' and 'finished', where 'instantaneous' comes from Latin 'instantaneus', meaning 'occurring at once', and 'finished' from Old French 'finir', meaning 'to end'.

'instantaneous' evolved from Latin 'instantaneus' through Middle English, while 'finished' evolved from Old French 'finir' to modern English 'finish'.

Initially, 'instantaneous' meant 'occurring at once', and 'finished' meant 'to end'. Together, they convey the idea of something being completed immediately.