sourdough
/ˈsaʊədəʊ/noun
1
- mass noun leaven for making bread, consisting of fermenting dough, originally that left over from a previous baking酵头。
1.1
- bread made using such leaven用酵头发面制成的面包。
2
- N. Amer. an experienced prospector in the western US or Canada; an old timer〈北美〉（美国西部或加拿大）有经验的探矿者; 老居民, 老职员, 老手。