(TARR-mack)

(n.) 1. Pavement made from layers of crushed stone, smoothed and coated with a tar binder (v. tr.) 2. To make an aircraft sit on a taxiway

John Loudon McAdam (1756-1836) was a Scotsman who served as general surveyor for all of England's highways. McAdam popularized a method of building roads that was a big improvement over traditional dirt roads. It involved spreading layers of small, broken stones over a gently sloping roadbed, then using the weight of passing traffic to crush the stones into uniform size. In McAdam's honor, this was called "macadamizing."

Roadbuilders soon improved on this with "tar-macadam," a method of smoothing the stones with a heavy roller, then adding tar to bind them. In 1903, "Tarmac" was registered as a proprietary name in the United States. Today we often hear it used generically, either as a noun or a verb.

"In fact, Gore and Bush have completely reversed accessibility standards--Gore comes back on Air Force 2 just about daily to rap with reporters, while with the exception of a brief Friday-night availability on a Florida tarmac a few weeks ago, Bush is hermetically sealed, safe from anyone who would ask him to explain his record or proposals."--Jake Tapper, in Salon.