‖abaciscusArch.|æbəˈsɪskəs|[L., a.Gr.ἀβακίσκος,dim.of ἄβαξ a slab.]1.‘A square compartment enclosing a part or the entire pattern or design of a Mosaic pavement.’ Gwilt.†2.‘Sometimes used as synonymous with abacus.’ Gwilt. Obs.