roadbed

The word 'roadbed' is a transparent compound formed within Modern English from two native Old English elements. The first element, 'road', evolved from the Old English 'rād', which originally referred to the act of riding or a journey, before narrowing to denote the prepared path or way itself. The second element, 'bed', derives from Old English 'bedd', which broadly meant a place for resting or a flat base, as seen in 'riverbed' or 'flowerbed'. When combined, the literal "bed for a road" logically creates the modern engineering term for the foundational layer that supports the pavement or tracks, ensuring stability and durability.

Structure: road + bed road: From Old English 'rād', meaning "a riding, journey on horseback, raid." Its functional role is the core concept of a path or way for travel. bed: From Old English 'bedd', meaning "a sleeping place, garden plot." Its functional role is to denote a base, foundation, or supporting layer.