Definition of "Allegheny"

(with "the") The Allegheny River in Pennsylvania.  examples

Allegheny Mountain (Pennsylvania), a major mountain ridge in the northern part of the Allegheny Mountains.  examples

Allegheny Mountain (West Virginia – Virginia), a major mountain ridge in the southern part of the Allegheny Mountains.  examples

(dated, attributively) The Allegheny Mountains.  examples

(dated, attributively) Appalachia.  examples

Any of several towns or counties in Pennsylvania, Virginia, North Carolina and Kentucky.  examples