ACANTHUS- CORINTHIAN ABACUS

 ACANTHUS- CORINTHIAN ABACUS 

ABACUS,

 in Arch.: a square or oblong level tablet on the capital of a column, and supporting the entablature. In the DoricM old Ionic, and Tuscan orders, the abacus is a regular oblong; but in the orders the abacus has oblong, but in the new Ionic, Corinthian, and Roman orders the abacus has concave sides,with truncated angles. Square marble tablets let into walls and fields with figures in them, inserted in mosaic floors, were also included under the term abacus in ancient architecture. 

References:

1.ALDEN'S MANIFOLD CYCLOPEDIA OF KNOWLEDGE AND LANGUAGE WITH ILLUSTRATIONS VOL 1 A TO AMERICA, NEW YORK JOHN B ALDEN PUBLISHER 1887