abacus

IPA/ˈæbəkəs/
KK[ˈæbəkəs]IPA/ˈæbəkəs/

abacus — noun

  • abacussingular
  • abacusesplural

1. a wooden or plastic counting device made up of beads that slide along thin rods

1.nounC1
Definition

a wooden or plastic counting device made up of beads that slide along thin rods inside a frame, used by hand to add, subtract, and do other simple math.

Example

Mr. Lin showed the children how to add numbers on a small wooden abacus.

collocation: add numbers on an abacus

Aiko's grandmother can multiply faster on an abacus than most people can on a phone.

comparative: faster on an abacus than

Common collocations
  • wooden abacus
  • Chinese abacus
  • use an abacus
  • beads on an abacus
  • calculate on an abacus
Synonyms
  • counting frame

    plain descriptive name, common in classroom contexts

  • soroban

    Japanese-style abacus with one bead above the bar and four below

  • suanpan

    traditional Chinese abacus with two beads above and five below

Usage Note

Almost always countable and singular with 'an'. The plural is usually spelled 'abacuses', though 'abaci' also appears in older texts. The verb most often used with it is 'use', followed by a 'to'-infinitive describing the calculation.

Common Mistakes

I calculated it by abacus.
I calculated it on an abacus.
use the preposition 'on' (or 'with'), not 'by', for the tool itself.
He bought two abacus.
He bought two abacuses.
the standard English plural adds '-es'.

2. in classical architecture, the flat square or shaped stone block that crowns a c

2.nounC2
Definition

in classical architecture, the flat square or shaped stone block that crowns a column's decorated head and directly supports the beam resting above it.

Example

The marble abacus on each Doric column carries the weight of the long stone beam above.

architecture: abacus on a column

On the temple in Athens, every abacus is cut from a single block of white stone.

Common collocations
  • marble abacus
  • abacus of a column
  • Doric abacus
  • square abacus
Synonyms
  • impost

    broader term for a stone block carrying an arch or beam

  • capstone

    general term for any top stone, not limited to columns

Antonyms
  • base

    the matching block at the bottom of a column

Usage Note

Restricted to architecture and art-history writing; learners are unlikely to meet this sense outside specialist texts. Often appears with words like 'capital', 'column', 'Doric', 'Ionic', or 'Corinthian'.

Common Mistakes

The abacus of the column had a clock on it.
The capital of the column had a clock on it.
the abacus is only the small flat top piece, not the whole decorated head.

Word family

  • abacuses
    nounC1
  • abaci
    nounC2

Synonym discussion

Sense: noun/1

All four words name tools used for arithmetic, but they differ in technology and culture. An 'abacus' is the general English name for any frame of beads moved by hand to count or calculate; it is mechanical, not electronic. A 'calculator' is a modern electronic device that does the math for you when you press buttons, so it requires no skill in moving beads. 'Counting frame' is a plain descriptive name often used for simple classroom abacuses given to young children learning numbers. 'Soroban' refers specifically to the Japanese style of abacus, with one bead above the bar and four below, and is taught as a serious mental-math discipline. So a child might learn on a counting frame, a Japanese student practises on a soroban, a market trader still uses an abacus, and an office worker reaches for a calculator.

abacuscalculatorcounting framesoroban

Common collocations

Nouns

  • abacus beads
  • abacus frame
  • abacus rod

Phrases

  • use an abacus
  • do sums on an abacus
  • slide the beads of an abacus

Prepositions

  • on an abacus
  • with an abacus

Etymology

SemiticGreekLatinEnglish

The word entered English in the late 1300s from Latin 'abacus', meaning a board or tray covered with sand or dust on which figures could be drawn for calculation. Latin took the word from Greek 'abax', which itself probably came from a Semitic root meaning 'dust' or 'sand'. As bead-and-rod counting devices replaced the older dust trays, the name stayed with the new tool. The much later architectural sense, naming the flat slab at the top of a column, comes from the same Latin word because that block resembled a small flat tray.