‖n.; pl. Abaculi [ L., dim. of abacus. ] (Arch.) A small tile of glass, marble, or other substance, of various colors, used in making ornamental patterns in mosaic pavements. Fairholt. [ 1913 Webster ]

n.; E. pl. Abacuses ; L. pl. Abaci [ L. abacus, abax, Gr. 'a`bax ] 1. A table or tray strewn with sand, anciently used for drawing, calculating, etc. [ Obs. ] [ 1913 Webster ]

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. [ 1913 Webster ]

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. [ 1913 Webster ]

4. A board, tray, or table, divided into perforated compartments, for holding cups, bottles, or the like; a kind of cupboard, buffet, or sideboard. [ 1913 Webster ]

Abacus harmonicus (Mus.), an ancient diagram showing the structure and disposition of the keys of an instrument. Crabb. [ 1913 Webster ]