The Collaborative International Dictionary
Substruction
Substruction \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.
--Evelyn.
Wiktionary
substruction
n. (context architecture English) 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