plural abaci ˈa-bə-ˌsī How to pronounce abacus (audio)
ə-ˈba-ˌkī How to pronounce abacus (audio)
or abacuses
: an instrument for performing calculations by sliding counters along rods or in grooves
: a slab that forms the uppermost member or division of the capital of a column

Illustration of abacus

Illustration of abacus
  • abacus 1

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Probably of Babylonian origin, an abacus is a calculating instrument that uses beads that slide along a series of wires or rods set in a frame to represent the decimal places. It is the ancestor of the modern digital calculator. Used by merchants in the Middle Ages throughout Europe and the Arabic world, it was gradually replaced by arithmetic based on Hindu-Arabic numerals. Though rarely used in Europe past the 18th century, it is still used in the Middle East, China, and Japan.

Examples of abacus in a Sentence

Recent Examples on the Web Pebbles as used on an abacus, to count out money, votes, and distances. Weike Wang, The New Yorker, 27 July 2023 Counting with bits works a little like counting on an abacus, but the column values are orders of two (128, 64, 32, 16, 8, 4, 2, 1). Charlotte Hu, Popular Science, 29 June 2023 Now consider a quantum abacus. Stephon Alexander, Wired, 31 Aug. 2021 Paper ballots should go the way of the abacus. Andy Kessler, WSJ, 1 Nov. 2020 There are rolling bunnies and whales, a plane, fire trucks, cars, a 3D elephant puzzle, boxes with drawers, a tic-tac-toe game built like an abacus and more. Holly Haber, Dallas News, 13 Dec. 2022 This is like the difference between building a stick-in-the-ground sundial versus a comparatively more complex accounting tool like an abacus, as one head of quantum research at a major Wall Street bank put it to me. Robert Hackett, Fortune, 8 Dec. 2020 The exhibit tracks milestones in the progress of computational technology from the abacus to your smart phone. Discover Magazine, 24 June 2011 The Guidestones are an abacus compared to Stonehenge’s computer. Jill Neimark, Discover Magazine, 9 Sep. 2013 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'abacus.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


Latin, from Greek abak-, abax, literally, slab

First Known Use

14th century, in the meaning defined at sense 1

Time Traveler
The first known use of abacus was in the 14th century

Dictionary Entries Near abacus

Cite this Entry

“Abacus.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/abacus. Accessed 2 Dec. 2023.

Kids Definition


plural abaci ˈab-ə-sī How to pronounce abacus (audio) -ˌkē How to pronounce abacus (audio)
or abacuses
: an instrument for making calculations by sliding counters along rods or in grooves

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