subbase

noun

sub·​base ˈsəb-ˌbās 

: underlying support placed below what is normally construed as a base: such as

a

: the lowest member horizontally of an architectural base or of a baseboard or pedestal

b

: pervious fill (such as crushed stone) placed under a roadbed

Examples of subbase in a Sentence

Recent Examples on the Web

According to the audit, streets are constructed in four levels — surface, base, subbase and subgrade — so a resurfaced road would not necessarily cure a flawed subgrade. —Jeff McDonald, sandiegouniontribune.com, 13 July 2017

Word History

First Known Use

1667, in the meaning defined above