'aftertax' originates from the combination of 'after' and 'tax', where 'after' means 'following' and 'tax' refers to a financial charge imposed by a government.

'aftertax' evolved from the combination of the words 'after' and 'tax' in English, maintaining its meaning over time.

Initially, it meant 'following the deduction of taxes', and this meaning has largely remained the same in modern usage.