The word 'subtract' is a direct borrowing from Latin 'subtractus', the past participle of 'subtrahere', meaning 'to draw away from below, to remove'. The Latin verb is composed of the prefix 'sub-' ('under') and 'trahere' ('to pull, draw'). The core logic is of pulling a quantity away from a main amount, as if drawing it out from underneath. This mathematical sense of taking one number away from another was established in English by the mid-16th century, building on the earlier, more general meaning of 'to withdraw or remove'.

Structure: sub (under) + tract (pull, draw) sub- (Latin prefix meaning 'under, below, from under'); -tract (from Latin verb 'trahere', meaning 'to pull, draw')