R / rūdĕrātĭo
noun

rūdĕrātĭo

gen. rūdĕrātōnis · gender feminine · decl. 3rd
a paving with rubbish; ruderation
a paving with rubbish, ruderation, Vitr. 7, 1.—
a mass of broken stone by extension
Transf., a mass of broken stone, Vitr. 5, 12, 6.