sourdough

Từ điển WordNet v3.1 - WordNet Dictionary

noun

1. a leaven of dough in which fermentation is active;
used by pioneers for making bread (Freq. 1)
• Hypernyms:
leaven, leavening
2. a settler or prospector (especially in western United States or northwest Canada and Alaska)
• Regions:
West, western United States
• Hypernyms:
settler, colonist, prospector