Subbases

Part of speech: noun

Definitions

1. Layers of compacted material laid beneath the base course to support a road, runway, or paved surface above them
2. Foundation courses of gravel or crushed stone placed under the main base of a pavement to spread loads and drain water
3. The lower structural layers of a road or pavement construction, lying under the base and carrying the traffic load

Etymology: "Subbases" is simply the plural of "subbase," a noun formed by attaching the prefix "sub-" ("under" or "below," from Latin "sub") to "base." The plural follows the regular English pattern of adding "-s" to the singular. A subbase, in the sense of a layer of material laid beneath a surface, is a compound of two ordinary English elements rather than a borrowed or coined term with a dramatic backstory. Its meaning follows directly from its parts: the "base" is the foundation, and the "sub-" places this layer beneath the surface above it, most often in road and construction work, where engineers speak of several such layers stacked beneath a finished pavement.