name for a group of related native people in the Columbia River region of Washington and Oregon, from Salishan /činuk/, name of a village site [Bright]. The name was extended to a type of salmon (1851) and a warm spring wind in that region (1860). Chinook jargon was a mishmash of native (Chinook and Nootka), French, and English words; it once was the lingua franca in the Pacific Northwest, and this sense is the earliest attested use of the word (1840).
"horse, Indian pony of the northern Rockies," 1841, American English, said to be a Chinook (native Pacific Northwest) word; also the name of an Indian group and language (1825), of unknown origin.
"(self-)important person," 1912, short for Chinook jargon high muck-a-muck, literally "plenty of food" from muckamuck "food" (1847), which is of unknown origin. Also mucky-muck; muckety-muck.
1845, among some American native peoples, "a gift," from Chinook jargon pot-latch, "a gift," from Nootka (Wakashan) patshatl "giving, gift." Later (1865) in sense "An Indian feast, often lasting several days, given to the tribe by a member who aspires to the position of chief, and whose reputation is estimated by the number and value of the gifts distributed at the feast" [Century Dictionary, 1895]