1838, John Phillips, “Portable Trigonometer” in Annual Report of the Royal Cornwall Polytechnic Society, volumes 6–7, page 120
It is capacitated to rule parallel lines of any length, with a regularity and proximity surpassing in these respects, the instruments it is intended to supersede; for this purpose, it has a vernier adapted to the decimated, or the duodecimated division of the unit of length.
The French squadron (consisting of two Russian vessels and a Dutch jolly-boat) opened fire at a distance far beyond the range of our rifles, and the carnage in our ranks was fearful. We were being gradually duodecimated when a happy thought struck me. I offered my services as a torpedo.
1899, Current Literature (Current Literature Pub. Co.), volume 25, page 116
He has duodecimated his difficulties by choosing twelve boy “heroes,” all very hard […]
1928, Sir John Collings Squire and Rolfe Arnold Scott-James, The London Mercury (Field Press Ltd), volume 18, page 446
Already he has epitomized, and so to speak, duodecimated, the Golden Bough, while Lady Frazer has culled a florilegium from his works for the benefit of those who revel in the graces of a pure and lofty style.
1966, Philip Elliot Slater, Microcosm: Structural, Psychological, and Religious Evolution in Groups (Wiley), page 73
First they think of each taking away what amounts to the role he has achieved in the group, but this seems not to suffice, and once again a fantasy of cannibalistic incorporation appears, this time in the form of the duodecimated coat.
1974, Jean d’Ormesson, The Glory of the Empire: A Novel, a History (Knopf, Random House; ISBN0394481216, 9780394481210), page 298
The barbarians were duodecimated — i.e., one out of every twelve was beheaded.
2009, Tom McMorrow, Having Fun With Words of Wit and Wisdom: In 3,401 Quotations from Writers Across the Ages: From the Prophets in the Bible to Barack Obama, page 75
And on a personal note for ancient Romans, if they had duodecimated a legion as punishment for rampant murder and rape rather than to decimate them (q.v.), two less guys per unit would have had to be killed.