Chow

“Chow” is a Chinese term and probably came into use in America in California in the 1850s. To the cowboy, “chow” meant something to eat.
 
 
Google Books
Dictionary of the American West:
Over 5,000 Terms and Expressions from Aarigaa! to Zopilote
by Win Blevins
Seattle, WA: Sasquatch Books
2001
by Pg. 83:
CHOW Food: CHUCK. The word evidently was borrowed from the Chinese in California. Along with the other great preoccupations of Westerners, such as sex, booze, and death, food has gotten a lot of names: chicken fixings (fancy food), chuck, chuckaway, DOINGS, FIXINGS, FLUFF DUFFS (fancy food again), kow-kow, MUCKAMUCK, soft grub (fancy food once more).
COMBINATIONS: chow line, chow time.
 
(Oxford English Dictionary)
chow, n.
Pidgin-English and slang. Food, or a meal, of any kind. Also spec. = CHOW-CHOW 1. Also attrib.
This sense is supposed to be due to the use of the chow (‘the edible dog of China’) as food by poor Chinese.
[1856 Spirit of Age (Sacramento) 27 Nov. 2/2 Ah Chowah in the Celestial lingo means Mr, Chow something good to eat.] 1886 YULE & BURNELL Hobson-Jobson 164/2 Chow is in ‘pigeon’ applied to food of any kind.