Deduction

How to spell deduction

9 letters · 3 syllables

How to pronounce deduction

Say the part in capitals loudest.

What does deduction mean?

1. nounAn amount that is taken away from a total, such as money removed from wages or taxable income.
2. nounThe process of reaching a conclusion by reasoning logically from known facts or general principles.

Deduction in a sentence

• The charity donation qualified as a tax deduction.

• By careful deduction, the detective identified the only possible suspect.

• Her payslip listed a deduction for the pension contribution.

• The auditor reached the figure through simple deduction from the records.

Where does deduction come from?

Language of origin: Latin

This word traces back to the Latin verb deducere, which literally meant 'to lead down' or 'to lead away', formed from the prefix de- meaning 'down' or 'from' and ducere meaning 'to lead'. The related noun deductio first described the act of leading something away or drawing it off, and over time it took on the more abstract sense of subtracting one amount from another. English borrowed the word through Old French in the late 1300s, and by the time logicians and philosophers picked it up, it had also acquired the meaning of drawing a conclusion by reasoning from general principles. The same Latin ducere root quietly sits inside many familiar relatives, including 'conduct', 'produce', 'reduce' and 'duct', all of which involve some kind of leading or channelling. Keeping that 'duct' core in mind helps explain why the word is spelled with the letters d-u-c-t in the middle rather than something that merely sounds right.

How the word is built

• de- (down, away)
• duct (lead, from Latin ducere)
• -ion (noun-forming suffix)