abacus

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A manual computing device consisting of a frame holding parallel rods strung with movable counters.
2. n. Architecture A slab on the top of the capital of a column.

Century Dictionary and Cyclopedia

1. n. A tray strewn with dust or sand, used in ancient times for calculating.
2. n. A contrivance for calculating, consisting of beads or balls strung on wires or rods set in a frame. The abacus was used, with some variations in form, by the Greeks and Romans, and is still in every-day use in many eastern countries, from Russia to Japan, for even the most complex calculations. The sand-strewn tray is supposed to have been introduced from Babylon into Greece by Pythagoras, who taught both arithmetic and geometry upon it; hence this form is sometimes called abacus Pythagoricus. In the form with movable balls, these are used simply as counters to record the successive stages of a mental operation. The sum shown in the annexed engraving of a Chinese abacus (called swanpan, or “reckoning-board”) is 5,196,301.
3. n. In architecture: The slab or plinth which forms the upper member of the capital of a column or pillar, and upon which rests, in classic styles, the lower surface of the architrave. In the Greek Doric it is thick and square, without sculptured decoration; in the Ionic order it is thinner, and ornamented with moldings on the sides; in the Corinthian also it is ornamented, and has concave sides and truncated corners. In medieval architecture the entablature was abandoned and the arch placed directly on the column or pillar; the abacus, however, was retained until the decline of the style. In Byzantine work it is often a deep block affiliated with classic examples. In western styles every variety of size, shape, and ornamentation occurs. The general use of a polygonal or round abacus, as more consonant with neighboring forms than the square shape, is one of the distinctive features of perfected Pointed architecture.
4. n. Any rectangular slab or piece; especially, a stone or marble tablet serving as a sideboard, shelf, or credence.
5. n. In Roman antiquity, a board divided into compartments, for use in a game of the nature of draughts, etc.
6. n. The mystic staff carried by the grand master of the Templars.
7. n. The structure and arrangement of the keys or pedals of a musical instrument.

GNU Webster's 1913

1. n. obsolete A table or tray strewn with sand, anciently used for drawing, calculating, etc.
2. 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.
3. n. The uppermost member or division of the capital of a column, immediately under the architrave. See Column.
4. n. A tablet, panel, or compartment in ornamented or mosaic work.
5. n. A board, tray, or table, divided into perforated compartments, for holding cups, bottles, or the like; a kind of cupboard, buffet, or sideboard.

WordNet 3.0

1. n. a tablet placed horizontally on top of the capital of a column as an aid in supporting the architrave
2. n. a calculator that performs arithmetic functions by manually sliding counters on rods or in grooves