Green’s Dictionary of Slang

(US) coffee; also attrib.

1899		Atlanta Constitution 17 July 5/4: ‘A dozen in the grease’ meant fried oysters; ‘one jamoca’ was for a cup of coffee.
1899		N.Y. Tribune 28 Aug. 12/6: [advert] Jamoke Blend. I lb cartons in beans or ground.
1900		J.I. Markey From Iowa to the Philippines 290: Numbers of the aforesaid friends would be present as the soldiers’ guests, and then it hustled the ‘Jamocha King’.
1921		P. & T. Casey Gay-cat 187: Coffee-royal’s better [...] There ain’t nothin’ stronger in the booze line than pure alky mixed with jamocha.
1927		C. Samolar ‘Argot of the Vagabond’ in AS II:9 389: Coffee is Jamoke (Java-Mocha).
1931		‘Scissor Bill’ in Irwin Amer. Tramp and Und. Sl. 247: He always will be satisfied until he’s dead / With sinkers and jamoka and a lousy old bed.
1934		G. & S. Lorimer Stag Line 168: Jamoke hits the spot, hey?
1935		W. Mahoney ‘TheRuse in Cocaine Alley’ in Und. Detective Mar. 🌐 Say, Mose, how about guzzling a cup of jamok?
1936		Mencken Amer. Lang. (4th edn) 580: In virtually all American prisons [...] coffee is jamoca (apparently from Java and Mocha).
1941		J. Smiley Hash House Lingo 7: An order for a cup of coffee may be given by [...] cup of jamoch.
1944		H. Hunt East of Farewell 6: ‘Coffee and cigarettes,’ Maxon said. ‘Jamoke and butts.’.
1948		J. Archibald ‘Klump a la Carte’ Popular Det. July 🌐 Willie turned his attention to finishing his own dunning missive while the jamoch perked.
1949		Monteleone Criminal Sl. (rev. edn) 131: jamoche Coffee.
1950		Goldin et al. DAUL 110/1: Jamoka. Coffee.
1958		L.F. Cooley Run For Home (1959) 94: Let’s go get a cup of ‘jamoke’.
1962		Ragen & Finston World’s Toughest Prison 805: jamoke – Coffee.
2004		E. Weiner Drop Dead, My Lovely (2005) 50: Grim-faced in her care not to spill a steaming mug of jamoke.