abacus

noun4

1. •
   A device used for performing arithmetical calculations; (rare) a table on which loose counters are placed, or (more commonly) an instrument with beads sliding on rods, or counters in grooves, with one row of beads or counters representing units, the next tens, etc.

   • I’ve heard merchants still use an abacus for adding things up in China.
2. •
   The uppermost portion of the capital of a column immediately under the architrave, in some cases a flat oblong or square slab, in others more decorated.

   • The shafts carry the usual cubical capitals—surmounted by plain heavy impost stones in place of moulded abaci—the one on the right being the better preserved. — 1942
3. •
   (historical) A board, tray, or table, divided into perforated compartments for holding bottles, cups, or the like; a kind of buffet, cupboard, or sideboard.
4. •
   (no longer used, historical) A table or tray scattered with sand which was used for calculating or drawing.