sourdough
sour.dough \'sau.(*)r-.do-\ n [fr. the use of sourdough for making bread in prospectors' camps] 1: a leaven of dough in which fermentation is active 2: a veteran inhabitant and esp. an old-time prospector of Alaska or northw estern Canada
Webster's English Dictionarysour.dough \'sau.(*)r-.do-\ n [fr. the use of sourdough for making bread in prospectors' camps] 1: a leaven of dough in which fermentation is active 2: a veteran inhabitant and esp. an old-time prospector of Alaska or northw estern Canada