from the GNU version of the Collaborative International Dictionary of English
- n. One of the tiles or squares of a tessellated pavement; an abaculus.
from The Century Dictionary and Cyclopedia
- n. In architecture, a diminutive of abacus in its various senses. Also called abaculus.
From New Latin, from Ancient Greek ἀβακίσκος (abakiskos, "a coloured stone for laying mosaic"), diminutive of ἄβαξ (abaks, "board"). See abacus. (Wiktionary)