subgrade

[suhb-greyd]Civil Engineering, Building Trades.

noun

the prepared earth surface on which a pavement or the ballast of a railroad track is placed or upon which the foundation of a structure is built.

adjective

beneath the finished ground level of a project.

Origin of subgrade

First recorded in 1895–1900; sub- + grade

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for subgrade

Historical Examples of subgrade

The side-walls and subgrade electric conduits were water-proofed with felt and pitch.
Transactions of the American Society of Civil Engineers, Vol. LXVIII, Sept. 1910
B. H. M. Hewett
In the subgrade telephone and telegraph ducts east of the Manhattan Shaft, much trouble was caused by grout in the ducts.
Transactions of the American Society of Civil Engineers, Vol. LXVIII, Sept. 1910
B. H. M. Hewett
When the work was finished, a subgrade reversed-grade drain carried the water to the shaft sump by gravity.
Transactions of the American Society of Civil Engineers, Vol. LXVIII, Sept. 1910
B. H. M. Hewett
Some engineers advocate that in preparing the subgrade, the earth be thoroughly rolled; others prefer not to roll the subgrade.
American Rural Highways
T. R. Agg
The pavement laid was bitulithic and the subgrade was an old macadam road built by the County.
Third Biennial Report of the Oregon State Highway Commission
S. Benson, W. L. Thompson, R. A. Booth, Herbert Nunn

British Dictionary definitions for subgrade

subgrade

noun

the ground beneath a roadway or pavement

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