'correctly-separated' originates from the combination of 'correctly' and 'separated', where 'correctly' is derived from Latin 'correctus', meaning 'set right', and 'separated' from Latin 'separatus', meaning 'to divide'.

'correctly-separated' evolved from the combination of the words 'correctly' and 'separated', which have been used in English since the Middle Ages.

Initially, it meant 'divided in a correct manner', and this meaning has largely remained the same in modern usage.