Definition of mid-atlantic:
(n) :
The middle of the East Coast of the United States, typically consisting of New York, New Jersey, Pennsylvania, Maryland, Delaware, Virginia, West Virginia, and Washington, DC.
(n) :
Used as an attributive modifier in compounds such as "mid-Atlantic current" and "Mid-Atlantic Ridge": located in, or otherwise relating to, the mid-Atlantic. See: Mid Atlantic Ridge
(n) :
(figuratively) Used as an attributive modifier in compounds such as "mid-Atlantic accent" and "mid-Atlantic English": half-American, half-European; combining American and European elements.
(adj) :
Of or relating to this region.
(n) :
The middle of the Atlantic Ocean.
(n) :
Used alone, with "the".