Sub*struc"tion (?), n. [L. substructio, fr. substruere, substructum, to build beneath; sub under + struere to build.] Arch.
Underbuilding; the foundation, or any preliminary structure intended to raise the lower floor or basement of a building above the natural level of the ground.
It is a magnificent strong building, with a substruction very remarkable.
© Webster 1913.