noun Date: 1826 underlying support placed below what is normally construed as a base: as, the lowest member horizontally of an architectural base or of a baseboard or pedestal, pervious fill (as crushed stone) placed under a roadbed
SUBBASE
Meaning of SUBBASE in English
Merriam Webster. Explanatory English dictionary Merriam Webster. Толковый словарь английского языка Мерриам-Уэбстер. 2012