abacus

 
Pronunciation: /ˈabəkəs/

noun (plural abacuses)

  • 1a simple device for calculating, consisting of a frame with rows of wires or grooves along which beads are slid.
  • 2 Architecture the flat slab on top of a capital, supporting the architrave.

Origin:

late Middle English (denoting a board strewn with sand on which to draw figures): from Latin, from Greek abax, abak- 'slab, drawing board', of Semitic origin; probably related to Hebrew 'āḇāq 'dust'