1449, creke "narrow inlet in a coastline," from kryk (c.1230), probably from O.N. kriki "nook," perhaps infl. by Anglo-Fr. crique, itself from a Scand. source via Norman. Perhaps ultimately related to crook. Extended to "inlet or short arm of a river" by 1577, which probably led to use for "small stream, brook" in Amer.Eng. (1622). Also used there and in Canada, Australia, New Zealand for "branch of a main river," possibly from explorers moving up main rivers and seeing and noting mouths of tributaries without knowing they often were extensive rivers of their own. Slang phrase up the creek "in trouble," often esp. "pregnant," first recorded 1941, perhaps originally armed forces slang for "lost while on patrol."
Indian tribe or confederation, 1725, named for creek, the geographical feature, and abbreviated from Ochese Creek Indians, from the stream in Ga. where English first encountered them. Native name is Muskogee, a word of uncertain origin.