• synonyms


[ab-uh-kuh s, uh-bak-uh s]
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noun, plural ab·a·cus·es, ab·a·ci [ab-uh-sahy, -kahy, uh-bak-ahy] /ˈæb əˌsaɪ, -ˌkaɪ, əˈbæk aɪ/.
  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.
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Origin of abacus

1350–1400; Middle English < Latin: board, counting board, re-formed < Greek ábax
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Related Words


Examples from the Web for abaci

Historical Examples

  • The little birds under the angles of the abaci should not be overlooked.

    Byzantine Churches in Constantinople

    Alexander Van Millingen

  • From these were derived the abaci of the Chinese and Russians.

    The Races of Man

    Joseph Deniker

  • The abaci of the capitals are either square or octagonal in plan.

  • In Romanesque and Gothic work the capitals with their abaci take the place of the impost mouldings.

  • The capitals here are very close imitations of Classical work, with the abaci frequently concave on plan.

British Dictionary definitions for abaci


noun plural -ci (-ˌsaɪ) or -cuses
  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
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Word Origin

C16: from Latin, from Greek abax board covered with sand for tracing calculations, from Hebrew ābhāq dust
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

Word Origin and History for abaci



late 14c., "sand table for drawing, calculating, etc.," from Latin abacus, from Greek abax (genitive abakos) "counting table," from Hebrew abaq "dust," from root a-b-q "to fly off." Originally a drawing board covered with dust or sand that could be written on to do mathematical equations. Specific reference to a counting frame is 17c. or later.

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Online Etymology Dictionary, © 2010 Douglas Harper