ca·vet·to 
(kə-vĕtō)
(kə-vĕtō)n. pl. ca·vet·ti (-vĕtē) or ca·vet·tos
A concave molding with a cross section that approximates a quarter circle.
[Italian, diminutive of cavo, hollow, from Latin cavus; see keuə- in the Appendix of Indo-European roots.]