# abacus

noun aba·cus \ ˈa-bə-kəs , ə-ˈba- \

## Definition of abacus

plural abaci\ˈa-bə-ˌsī, -ˌkē; ə-ˈba-ˌkī\ or abacuses
1 : an instrument for performing calculations by sliding counters along rods or in grooves
2 : a slab that forms the uppermost member or division of the capital of a column

## Did You Know?

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.

## Origin and Etymology of abacus

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

abacus

## What It Is

An abacus is a counting device that performs basic mathematical functions.

## How It Works

The abacus is believed to have been developed in the ancient Near East in the third millennium BCE. An abacus consists of a series of thin parallel bars set into a rectangular frame, usually made of wood. Each bar contains a number of beads that slide along its length. Individuals use the beads as number counters and use the abacus to perform addition, subtraction, multiplication, and division.

## Why It Matters

The abacus has been in continuous use since its conception. It is still widely used in Far Eastern cultures including China and Japan.

## Definition of abacus for English Language Learners

• : a device used for counting and calculating by sliding small balls or beads along rods or in grooves

## abacus

noun aba·cus \ ˈa-bə-kəs \

## Definition of abacus for Students

plural abaci \ˈa-bə-ˌsī\ or abacuses
: an instrument for doing arithmetic by sliding counters along rods or in grooves

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