deduce

Etymology

From Late Middle English deducen (“to demonstrate, prove, show; to argue, infer; to bring, lead; to turn (something) to a use; to deduct”), borrowed from Latin dēdūcere, the present active infinitive of dēdūcō (“to lead or bring out or away; to accompany, conduct, escort; (figuratively) to derive, discover, deduce”); from dē- (prefix meaning ‘from, away from’) + dūcere (the present active infinitive of dūcō (“to conduct, guide, lead; to draw, pull; to consider, regard, think”), ultimately from Proto-Indo-European *dewk- (“to lead; to draw, pull”)).

verb

1. (transitive) To reach (a conclusion) by applying rules of logic or other forms of reasoning to given premises or known facts.
   [T]he puritan buyldeth directly vpon the proteſtants firſt groundes in religion, & deduceth therof clearly and by ordinary conſequence al his concluſions, which the proteſtant cannot deny by divinity, but only by pollicy & humane ordination, or by turning to catholique anſwers contrary to ther owne principles: […] 11 September 1593, Robert Persons?], “The Second Parte of This Letter Conteyning Certaine Considerations of State vppon the Former Relation”, in Henry Walpole], transl., Nevves from Spayne and Holland Conteyning an Information of Inglish Affayres in Spayne vvith a Conferrence Made theruppon in Amsterdame of Holland.[…], [Amsterdam: A. Conincx], →OCLC, [https://books.google.com/books?id=YttlAAAAcAAJ&pg=PA29-IA1 folio [29], recto and verso]
   From the comparative weight or lightneſs of the Air at different times, he deduceth alſo the riſing and falling of Vapours in it. 24 April 1685, [John] Wallis, “A Discourse Concerning the Air’s Gravity, Observd in the Baroscope, Occasioned by that of Dr. [George] Garden;[…]”, in Philosophical Transactions: Giving Some Accompt of the Present Undertakings, Studies and Labours of the Ingenious in Many Considerable Parts of the World, volume XV, number 171, Oxford, Oxfordshire: […] Sam[uel] Smith […]; and Hen[ry] Clements[…], published 20 May 1685 [[Unsupported titles/`lsqb`Julian calendar|[Julian calendar]]; 30 May 1685], →DOI, →OCLC, page 1007
   Now Principles, when deduced by Diſcourſe of ſound Reaſon, may, from the Content of Mankind, take the Name and Force of a Law; but the Faculty which deduceth thoſe Principles, cannot with the leaſt Propriety be deemed a Law. This is confounding Cauſes with Effects, and attributing the Property to the Faculty creating, which only belongs to the Subject created. 1756, “An Abstract of the Reciprocal Duties of Representatives and Their Constituents, on Constitutional Principles”, in A New System of Patriot Policy. Containing the Genuine Recantation of the British Cicero.[…], London: […] Jacob Robinson,[…], →OCLC, section IV, page 39
2. (transitive) To examine, explain, or record (something) in an orderly manner.
3. (transitive, archaic) To obtain (something) from some source; to derive.
   The Spring whence thou Hugh Myddelton] deduced'st the ample stream, / The Poet's and Historian's theme, / Trenching thy mighty aqueduct a way, / 'Till as the humble plains, the aspiring hills obey. 1821 July, A. Heraud John Abraham Heraud?], “Apostrophe to the New River”, in Sylvanus Urban [pseudonym], editor, The Gentleman’s Magazine: And Historical Chronicle, volume XCI, part 2 (New Series, volume XIV), London: […] John Nichols and Son,[…]; and sold by John Harris and Son (successors to Mrs. [Elizabeth] Newbery),[…]; and by Perthes and Besser,[…], →OCLC, page 66, column 2
   Do not, my children, O do not accustom yourselves to such warfares, / Nor on your country's vitals thus turn your invincible valor: / Sooner refrain thou, thou who deducest thy race from Olympus! 1888, Virgil, “Book VI”, in Oliver Crane, transl., Virgil’s Æneid,[…], New York, N.Y.: The Baker & Taylor Co.,[…], →OCLC, lines 832–834, page 123
4. (intransitive, archaic) To be derived or obtained from some source.
5. (transitive, obsolete) To take away (something); to deduct, to subtract (something).
   to deduce a part from the whole
6. (transitive, obsolete, based on the word’s Latin etymon) To lead (something) forth.