Philly cheesesteak

Etymology
Named after Philly (Philadelphia).

Noun

 * 1) A cheesesteak sandwich made according to the classic Philadelphia recipe of melted cheese, sliced onions and thinly sliced pieces of beefsteak on a hoagie roll.

Usage notes
This term can be used on its own as a synonym for cheesesteak or to distinguish the original from a variation that substitutes other ingredients such as chicken cheesesteak or Hawaiian cheesesteak.