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abacus

American  
[ab-uh-kuhs, uh-bak-uhs] / ˈæb ə kəs, əˈbæk əs /

noun

plural

abacuses, abaci
  1. a device for making arithmetic calculations, consisting of a frame set with rods on which balls or beads are moved.

  2. Architecture. a slab forming the top of the capital of a column.


abacus British  
/ ˈæbəkəs /

noun

  1. a counting device that consists of a frame holding rods on which a specific number of beads are free to move. Each rod designates a given denomination, such as units, tens, hundreds, etc, in the decimal system, and each bead represents a digit or a specific number of digits

  2. architect the flat upper part of the capital of a column

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of abacus

1350–1400; Middle English < Latin: board, counting board, re-formed < Greek ábax

Explanation

An abacus is an ancient tool used for calculating that remains popular in some places even today. Some sort of counter (beads, beans, stones) is moved in a groove or on a wire to represent the different numbers in the equation. Abacus is a Latin word from a Greek word abax, which meant "counting table." The original abaci were created in sand. The plural abacuses can also be used. In architecture, an abacus can also refer to a flat slab that sits on top of the broad part of a pillar or column (called the capital) to help support a beam (called an architrave) that rests across several pillars.

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Vocabulary lists containing abacus

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Calculators, cars and probably candles and the abacus were considered a menace to society.

From The Wall Street Journal • Dec. 7, 2025

For example, you can add numbers perfectly using an abacus, in which wooden beads are pushed back and forth to represent arithmetic operations.

From Science Daily • Oct. 30, 2023

With an abacus and a slide rule, earlier helpmeets, you had to know something of the mathematical process.

From Washington Post • Apr. 28, 2023

You can put away the abacus for this year though.

From BBC • Dec. 9, 2022

Cassiopeia sat by the window, idly flicking the beads on the abacus up and down.

From "The Incorrigible Children of Ashton Place: Book I: The Mysterious Howling" by Maryrose Wood