1) Ancient Egyptian architecture 2) Molding 3) Moulding 
• (n.) A concave molding; -- used chiefly in classical architecture. See Illust. of Column.
See mouldings.
Ca·vet'to (kȧ*vĕt'to) noun [ Italian cavetto , from cavo hollow, Latin cavus .] (Architecture) A concave molding; -- used chiefly in classical architecture. See Illust. of Column . 
In architecture, a cavetto is a concave moulding of one quarter of a circle. They were used chiefly in the Grecian and other classical architecture.
[n] - a concave molding shaped like a quarter circle in cross section
cavetto (s), cavetti (pl) A concave architectural molding with a curve that is roughly a quarter circle (Italian, diminutive of cavo, hollow; from Latin cavus).
noun a concave molding shaped like a quarter circle in cross section