Meaning of SUBBASE in English

SUBBASE

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

Merriam Webster. Explanatory English dictionary Merriam Webster.      Толковый словарь английского языка Мерриам-Уэбстер.