Ab"a*cus (ăb"ȧ*kŭs), n.;
E. pl. Abacuses ; L. pl. Abaci
(-sī). [L. abacus, abax, Gr. 'a`bax]
1. A table or tray strewn with sand, anciently used
for drawing, calculating, etc. [Obs.]
2. 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.
3. (Arch.) (a) The uppermost
member or division of the capital of a column, immediately under the
architrave. See Column. (b) A tablet,
panel, or compartment in ornamented or mosaic work.
4. A board, tray, or table, divided into perforated
compartments, for holding cups, bottles, or the like; a kind of cupboard,
buffet, or sideboard.
Abacus harmonicus (Mus.), an ancient
diagram showing the structure and disposition of the keys of an