Green’s Dictionary of Slang

1. a hamburger.

1939

G. Rector Dinging in N.Y. 111: Our old friend hamburger can masquerade as Salisbury steak, Baltimore steak, and a multitude of other things.

2. (US, also Baltimore) liver.

1943		N. Shea WAACS 80: Baltimore steak: Liver.
1944		P. Kendall Dict. Service Sl. n.p.: Baltimore . . . liver.