macadam
Meaning
A road surface made of layers of compacted small broken stone, now usually bound with tar or asphalt.
Structure
Usage
The old highway was originally paved with macadam.
The driveway was constructed using a compacted layer of macadam.
Modern asphalt roads often have a base course of macadam.
Etymology
The word 'macadam' is a direct eponym, originating from the surname of Scottish engineer John Loudon McAdam (1756–1836). He pioneered a revolutionary method of road construction in the early 19th century, which involved compacting layers of small, angular stones to create a smooth, durable, and well-drained surface. The term, first recorded in 1824, transitioned from simply crediting the inventor ('McAdam's method') to becoming the generic name for the material and the technique itself. Later developments, such as using tar as a binder, led to the compound term 'tarmacadam' (shortened to 'tarmac'), but 'macadam' remains the core term for the broken-stone foundation of modern pavements.
Analysis
The entire word is an eponym derived from the surname of its inventor, John Loudon McAdam. It does not consist of productive, separable morphemes in English.