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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.

That speech raised his profile both abroad and at home, said David Coletto, a Canadian pollster and CEO of Abacus Data.

From BBC • Apr. 26, 2026

Karlyn Jones of Abacus Planning Group in Columbia, S.C., looks for higher deductibles for her clients — usually $1,000 or more.

From MarketWatch • Apr. 21, 2026

His party leads the provincial opposition, 51% to 25%, according to the polling firm Abacus Data.

From The Wall Street Journal • Oct. 24, 2025

Securities and Exchange Commission to resolve charges that it cheated Abacus investors by concealing Paulson's role, including how he made a $1 billion profit by betting that the sale of collateralized debt obligations would fail.

From Reuters • Aug. 10, 2023

Hanel, in the Ionick Capital, is that part which is under the Abacus, and lies upon Echinus or Egg, and which has its Contours or Turnings on every side to make the Voluta’s.

From An Abridgment of the Architecture of Vitruvius Containing a System of the Whole Works of that Author by Perrault, Claude