substructĭo, ōnis, f. [substruo],
an under - building , foundation , substructure , Vitr. 1, 5: maxima debet esse cura substructionum, id. 6, 11: maximae, Caes. B. C. 2, 25: insanae, Cic. Mil. 20, 53; 31, 85; Liv. 38, 28; Front. Aquaed. 3, 5 sq.; Col. 1, 5, 9; v. substruo fin.