'separately-maintained' originates from the combination of 'separate' and 'maintain,' where 'separate' comes from Latin 'separatus,' meaning 'to divide,' and 'maintain' from Latin 'manutenere,' meaning 'to hold in the hand.'

'separatus' transformed into the Old French word 'separer,' and 'manutenere' became 'maintenir' in Old French, eventually forming the modern English words 'separate' and 'maintain.'

Initially, 'separate' meant 'to divide,' and 'maintain' meant 'to hold,' but together they evolved to mean 'kept independently.'