Abacus n. : A table or tray strewn with sand, anciently used for drawing, calculating, etc.

Abacus n. : 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. It is still employed in China.

Abacus n. : The uppermost member or division of the capital of a column, immediately under the architrave. See Column.

Abacus n. : A tablet, panel, or compartment in ornamented or mosaic work.

Abacus n. : A board, tray, or table, divided into perforated compartments, for holding cups, bottles, or the like; a kind of cupboard, buffet, or sideboard.

Example:
What are the benefits of learning the Abacus?

Taxonomy
abacus, beads, Nepohualtzintzin, wire, Russian abacus, Chinese abacus, suanpan, grooves, calculations, Roman abacus, the Chinese, Japanese abacus, the Roman, The Russian, bead wire, instrument, Abacus logic, School.

Defination from the web:
abacus, also called a counting frame, is a calculating tool used primarily in parts of Asia for performing arithmetic processes. ... The abacus was in use centuries before the adoption of the written modern numeral system and is still widely used by merchants, traders and ...