Green’s Dictionary of Slang

(US tramp) a vegetable stew.

1926		Maines & Grant Wise-crack Dict. 7/1: Combination – Hobo term for regular meal.
1927		‘Jargon of the Und.’ in DN V x 442: Combination, A stew containing a little of everything the tramp can beg or steal.
1932		W.R. Burnett Giant Swing 177: The Greek was impassive. ‘Hello! What you want?’ ‘Combination and coffee.’ ‘Wan combinacion [sic], Java’.
1950		J.T. Farrell ‘Milly and the Porker’ in Amer. Dream Girl (1950) 195: ‘Adam ’n Eve on a raft. Wreck ’em ... an’ a Combinashun!’ Milly, the shapely waitress, shouted in a coarse voice.