Pronunciation: (at-lan'tik),[key] —adj. 1. of or pertaining to the Atlantic Ocean.
2. of, pertaining to, or situated on the eastern seaboard of the U.S.: the Atlantic states. 3. of or pertaining to the countries bordering the Atlantic Ocean, esp. those of North America and Europe.
4. of or pertaining to the North Atlantic Treaty Organization or its members: the Atlantic Alliance.
—n. 1. See Atlantic Ocean. 2. Railroads.a steam locomotive having a four-wheeled front truck, four driving wheels, and a two-wheeled rear truck. See table under Whyte classification.