macadam

noun

mac·​ad·​am mə-ˈka-dəm 

: macadamized roadway or pavement especially with a bituminous binder

Did you know?

John Loudon McAdam and Macadam

In 1783, inventor John Loudon McAdam returned to his native Scotland after amassing a fortune in New York City. He became the road trustee for his district and quickly set his inventiveness to remedying the terrible condition of local roads. After numerous experiments, he created a new road surfacing material made of bits of stone that became compressed into a solid mass as traffic passed over them. His invention revolutionized road construction and transportation, and engineers and the public alike honored him by using his name (respelled macadam) as a generic term for the material or pavement made from it. He is further immortalized in the verb macadamize, which names the process of installing macadam on a road.

Examples of macadam in a Sentence

Recent Examples on the Web

Route 40 spans the nation from the waters of the Atlantic Ocean off Atlantic City, New Jersey, through parts of Maryland, to those of the Pacific off San Francisco, some 3,000-plus miles across the country’s midsection like a great macadam belt. —Frederick N. Rasmussen, Baltimore Sun, 13 Feb. 2024

Crushed stone or even macadam became the roads’ base. —Mary Ann Ashcraft, baltimoresun.com/maryland/carroll, 11 Oct. 2019

The macadam on Tenth Street comes out of the winter in wretched condition. —Arthur Hart, idahostatesman, 30 June 2018

Word History

Etymology

after John Loudon McAdam †1836 Scottish civil engineer who introduced this method of road construction

First Known Use

1824, in the meaning defined above

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Kids Definition

macadam

noun

mac·​ad·​am mə-ˈkad-əm 

: a roadway or pavement constructed by compacting a layer of small broken stone along with a binder (as cement or asphalt)

macadamize

-ə-ˌmīz

verb

Etymology

named for John L. McAdam 1756–1836 Scottish engineer who invented the paving process