Other forms: deductions
A deduction is a conclusion you reach by reasoning down from something you already accept. Every shop on the street shuts at six; it is half past six; so the shop is shut. That last step is the deduction.
This is the Sherlock Holmes word, and Holmes has quietly bent it: strict deduction runs from a general rule to a particular case, while induction runs the other way, piling up particular cases until a rule appears - which is closer to what Holmes does with cigar ash. The other everyday sense has nothing to do with thinking at all: a deduction is an amount taken off a total, so a payslip lists deductions for tax and pension. The two verbs behind it are easy to swap by mistake, since you deduce a conclusion but you deduct a sum, and both land on the same noun. For the reasoning sense the adjective is deductive.
1noundeductionA conclusion reached by reasoning from a general rule to a particular case, or the process of reasoning that way.~29%
“From the mud on the boots he made the obvious deduction and rang the farm.”
synonyms: inference, conclusion
2nounamountAn amount taken away from a total.~71%
“After deductions, her take-home pay was less than she expected.”
Shares are an estimate: a language model read 14 sentences found in the wild and placed 14 of them on a sense — a count of our sample, not a measurement of English.
deduction is a form of reasoning.
Deduction came through Middle French deduction from Latin deductio. English then built the same word twice from its own stock - deduct plus -ion, and deduce plus -tion - which is why one noun ends up covering both the money taken off a bill and the conclusion drawn from a clue.
Latin
deductio
Middle French
déduction
English, today
deduction
From Middle French déduction, from Latin deductio. Equivalent to deduct + ion or deduce + tion.
Etymology from Wiktionary, CC BY-SA