A calculating table or frame; an instrument for performing arithmetical calculations by balls sliding on wires, or counters in grooves, the lowest line representing units, the second line, tens, etc
I've heard merchants still use an abacus for adding things up in China.
A small frame with wires stretched across it Each wire contains ten movable balls, which can be shifted backwards or forwards, so as to vary ad libitum the number in two or more blocks It is used to teach children addition and subtraction The ancient Greeks and Romans employed it for calculations, and so do the Chinese The word is derived from the Phoen abak (dust); the Orientals used tables covered with dust for ciphering and diagrams In Turkish schools this method is still used for teaching writing The multiplication table invented by Pythagoras is called Abacus Pythagoricus (Latin, abacus)
a calculator that performs arithmetic functions by manually sliding counters on rods or in grooves a tablet placed horizontally on top of the capital of a column as an aid in supporting the architrave
An abacus is a frame used for counting. It has rods with sliding beads on them. Calculating instrument that uses beads that slide along a series of wires or rods set in a frame to represent the decimal places. Probably of Babylonian origin, 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