Etymology The verb is first attested in 1591, the noun in 1641; borrowed from Latin decimātus, perfect passive participle of decimō (“to kill one tenth; to tithe”) (see, from -ate (verb-forming suffix) and -ate (noun-forming suffix)), from decimus (“tenth”) + -ō (verb-forming suffix). As a noun, via Latin decimatus (“tithing area; tithing rights”).
Archaic To kill one-tenth of (a group), (historical, specifically) as a military punishment in the Roman army selected by lot, usually carried out by the surviving soldiers.
God sometimes decimates or tithes delinquent persons, and they died for a common crime, according as God hath cast their lot in the decrees of predestination.c. 1650, Jeremy Taylor, Vol. I
Said to have been martyred as a Christian legionary commander of late Roman times for having refused an imperial order to kill one in ten (that is, decimate in the Roman meaning of the word) of the soldiers of another legion which had gone into revolt...1989, Basil Davidson, “The Ancient World and Africa”, in Egypt Revisited, page 49:
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...where Caesar threatened to disband Legio X after a mutiny. The men begged him to decimate them instead, and Caesar relented in the same way that Titus refrained from executing this cavalryman after his comrades’ appeal.1998, Adrian Goldsworthy, The Roman Army at War, page 263:
Shall we decimate them? That sounds good, nice word. Remove one-tenth of the population!2007, Russell T. Davies, “The Sound of Drums”, in Doctor Who:
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To destroy or remove one-tenth of (something).
...there will be eight hundred and ten laborers producing as nine hundred, while, to accomplish their purpose, they would have to produce as one thousand... Here, then, we have a society which is continually decimating itself...1840, P.J. Proudhon, What is Property?, page 164:
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Broadly To devastate: to reduce or destroy significantly but not completely.
[England] had decimated itself for a question which involved no principle, and led to no result.p. 1856, James Froude, History of England from the fall of Wolsey to the death of Elizabeth:
Um, some sort of power overload. I'm afraid it decimated your breakfast.1996, Star Trek: Voyager (TV series), Flashback (episode)
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They can be devastating to certain plants if left uncontrolled: a downy mildew of grapes decimated European vineyards during the nineteenth century.2001, Otis C. Maloy, Timothy D. Murray, et al., Encyclopedia of Plant Pathology, volume 1, page 379:
Captain Anderson: Commander Shepard did the right thing. We had to hold our fleet back to go after Sovereign. It was the only way. / Ambassador Udina: I agree, but this also presents us with an opportunity. The Council is dead. The galaxy is looking for leadership. / Ambassador Udina: The Citadel fleets were decimated in the attack. Their losses have made the Alliance stronger. If we step forward now, nobody will be able to stop us!2008, BioWare, Mass Effect (Science Fiction), Redwood City: Electronic Arts, →ISBN, →OCLC, PC, scene: Citadel:
What this attack represents is more powerful than the attack sequence itself, which is a double-edged sword, but let’s start with the positive. If what we see is any indication, Euron has decimated Yara’s fleet and cut it off before it was able to fetch the Dornish army.2017 July 23, Brandon Nowalk, “The great game begins with a bang on Game Of Thrones (newbies)”, in The Onion AV Club, archived from the original on 17 Aug 2017:
You forge theſe things prettily; but I have heard you are as poor as a decimated Cavalier [referring to Cromwell's ten per cent. income-tax on Cavaliers], and had not one foot of land in all the vvorld.1667 (revival performance), John Dryden, The Wild Gallant: A Comedy. […], In the Savoy [London]: […] T[homas] Newcomb for H[enry] Herringman, […], published 1669, →OCLC, Act II, page 18:
In addition, an ordinance was published that “all who had ever borne arms for the king, or declared themselves to be of the royal party, should be decimated, that is, pay a tenth part of all the estate which they had left, to support the charge which the commonwealth was put to...1819, John Lingard, History of England, page 352:
[I]t is a deed of higheſt charitie to help undeceive the people, and a vvork vvorthieſt your autoritie, in all things els authors, aſſertors and novv recoverers of our libertie, to deliver us, the only people of all Proteſtants left ſtill undeliverd, from the oppreſſions of a Simonious decimating clergie; […]1659, J[ohn] M[ilton], “To the Parlament of the Commonwealth of England with the Dominions therof”, in Considerations Touching the Likeliest Means to Remove Hirelings out of the Church. […], London: […] T[homas] N[ewcombe] for L[ivewell] Chapman […], →OCLC:
For example, in multiplying 3 by 0.2, the 3 units have to be decimated—that is, divided into 10 equal parts, obtaining 3 “deci-units” for each part, and then 2 such parts taken, giving as the answer 6 deci-units, or 0.6.1910 January, “Multiplication of Decimals”, in The Practical Teacher, volume 30, number 7, page 414:
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Proscribed To reduce to one-tenth: to destroy or remove nine-tenths of (something).
In this dramatic picture, the nation is literally decimated, and even the tenth which remains is subjected to a further destruction.1998, H. Wayne House, editor, Israel, the Land and the People, page 63:
African slaves were needed to replace Native American populations that had been decimated (literally reduced to one-tenth their size) by European conquest.2003, Susan S. Hunter, Black Death, page 58:
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In the New World, European colonists initially enslaved Native Americans, decimating the indigenous populations to one-tenth of their original sizes.2005, Wilma A. Dunaway, “Put in Master’s Pocket”, in Appalachians and Race, page 116:
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Computer graphics, Computing, Engineering, Mathematics, Natural sciences, Physical sciences, Sciences To replace (a high-resolution model) with another of lower but acceptable quality. (Usually algorithmically)
A decimate tool allows us to obtain a more coarse-grained view of the data over the full n-dimensional space.1999, Mihalisin & al., "Visualizing Multivariate Functions, Data and Distributions" in Readings in Information Visualization: Using Vision to Think, page 122
However, many times it is more practical to decimate existing high-res models because of time, money or manpower issues.2001, Inside 3Ds Max 4, page 56:
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Given this initial fine mesh, we smooth and decimate it to a desired mesh resolution.2004, Geremy Heitz et al., “Automatic Generation of Shape Models using Nonrigid Registration with a Single Segmented Template Mesh”, in Vision Modeling and Visualization 2004, page 74:
Etymology The verb is first attested in 1591, the noun in 1641; borrowed from Latin decimātus, perfect passive participle of decimō (“to kill one tenth; to tithe”) (see, from -ate (verb-forming suffix) and -ate (noun-forming suffix)), from decimus (“tenth”) + -ō (verb-forming suffix). As a noun, via Latin decimatus (“tithing area; tithing rights”).