abacus

Noun

abacus (plural abaci or abacuses)

1. (historical, obsolete) A table or tray scattered with sand which was used for calculating or drawing.
   • He [Gerebertus] was þe firste þat took abacus of Sarsyns, and ȝaf rules þerynne, þat mowe unneþe be understonde of þe kunnyngeste men of þe craft, þe whiche craftes men beþ cleped abaciste. Marianus. Abacus is a table wiþ þhe whiche schappes be portrayed and i-peynt in powdre, and abacus is a craft...[a. 1387, Ranulphi Higden [i.e., Ranulf Higden], chapter X, in John Trevisa, transl., edited by Joseph Rawson Lumby, Polychronicon Ranulphi Higden Monachi Cestrensis; together with the English...
   • [H]e set fondly and furiously to work upon [Thomas] Simpson's Euclid, [...] The smooth grassy sod answered all the purposes of the abacus, and the cows generously supplied him in a substitute for sand. Spreading and smoothing that substitute with his bear foot, he engraved upon it with his finger...1825, “a modern Greek” [pseudonym; Robert Mudie], “Education of the Athens”, in The Modern Athens: A Dissection and Demonstration of Men and Things in the Scotch Capital, 2nd edition, London: Printed...
2. A device used for performing arithmetical calculations; (rare) a table on which loose counters are placed, or (more commonly) an instrument with beads sliding on rods, or counters in grooves, with one row of beads or counters representing units, the next tens, etc.
   • I’ve heard merchants still use an abacus for adding things up in China.
   • Before leaving the question of early arithmetic I should mention that for practical purposes the almost universal use of the abacus or swan-pan rendered it easy to add or subtract, or even to multiply and divide, without any knowledge of theoretical mathematics. [...] [I]t will be sufficient here...1888, Walter W[illiam] Rouse Ball, “Egyptian and Phœnecian Mathematics”, in A Short Account of the History of Mathematics, London; New York, N.Y.: Macmillan and Co., →OCLC, page 6
3. The uppermost portion of the capital of a column immediately under the architrave, in some cases a flat oblong or square slab, in others more decorated.
   • The only mouldings uſed, both by the Saxon and Norman architects, were the torus, the ſcotia or reverſed torus, the cavetto or hollow moulding, and a kind of chamfered faſcia, which latter was generally uſed for impoſts or abacuſes to their capitals.1795 June 11, 18, 25, William Wilkins, “XIV. An Essay towards the History of the Venta Icenorum of the Romans, and of Norwich Castle; with Remarks on the Architecture of the Anglo-Saxons and Normans....
   • At Amiens, the square form of the abaci, and the volutes of the capitals, afford a decisive proof that the Norman fashion had not yet been superseded. On the other hand, at Salisbury, the abaci are mostly round, and where foliage is used in the capitals, their graceful and luxurious design clearly...1829 June, “Cathedrals of Salisbury and Amiens Compared, by the Late Rev. G. D. Whittington, in the Sixth Chapter of His ‘Survey of the Ecclesiastical Antiquities of France.’ 1811.”, in The Crypt, or...
4. (Ancient-Rome, historical, Ancient Greece) A board, tray, or table, divided into perforated compartments for holding bottles, cups, or the like; a kind of buffet, cupboard, or sideboard.
   • ABACUS, among the ancients, was a kind of cupboard or buffet. Livy, deſcribing the luxury into which the Romans degenerated after the conqueſt of Aſia, ſays they had their abaci, beds, &c. plated over with gold.1817, “ABACUS”, in Encyclopaedia Britannica: Or, A Dictionary of Arts, Sciences, and Miscellaneous Literature, 5th enlarged and improved edition, volume I, Edinburgh: Printed at the Encyclopædia...
   • The plate and nicknacks, always found in elegant Roman houses, were displayed on small one or three legged tables (trapezophoron), the slabs of which (abacus, a word which, like trapezophoron, is sometimes used for the whole table) had raised edges round them: several richly ornamented specimens of...1875, E[rnst Karl] Guhl, W[ilhelm David] Koner, “The Romans”, in F[rancis] Hueffer, transl., The Life of the Greeks and Romans, Described from Antique Monuments: Translated from the Third German...