- Dialectal leaven
- fermenting dough saved from one baking to be used for producing fermentation in a later one, thus avoiding the need for fresh yeast
- bread made with such doughin full sourdough bread
- a prospector or settler in the W U.S. or Canada, esp. one living alone: so called because their staple was sourdough bread
- a. Sour fermented dough used as leaven in making bread.b. Bread made from such a leaven.
- An early settler or prospector, especially in Alaska and northwest Canada.
Origin of sourdoughSense 2, from an association with using pieces of sourdough to leaven bread in the winter.
- Dough, leavened with yeast and lactobacteria that produce acids giving a sour taste.
- (slang) An old-timer, especially in Alaska. From the distinctive pouches of bread starter worn on a belt or around the neck by experienced prospectors during the Klondike Gold Rush.  
- (Yukon) A permanent resident of the territory. Someone who has lived in the Yukon during all four seasons.
- (someone new to Alaska and Yukon): cheechako