deduction
UK: dɪˈdʌkʃn | US: dɪˈdʌkʃn
n. the action of subtracting or taking away an amount
n. the process of reasoning from general principles to specific conclusions
n. an amount subtracted from a total
The word "deduction" originates from Latin deductio, combining de- (meaning "down" or "away") and ducere (meaning "to lead"). The morpheme duct preserves the core idea of "leading," while de- implies a movement away or reduction. Over time, the term evolved to encompass both logical reasoning (leading to a conclusion) and mathematical subtraction (taking away). The suffix -ion nominalizes the action, solidifying its modern meanings.
The detective used logical deduction to solve the mystery.
Tax deductions can reduce your taxable income.
Her argument was based on sound deductive reasoning.
The bank made a deduction from his account for the service fee.
Philosophers often study the principles of deduction in logic.