sour·dough 
(sourdō′)
(sourdō′)n.
1.
a. Sour fermented dough used as leaven in making bread.
b. Bread made from such a leaven.
2. An early settler or prospector, especially in Alaska and northwest Canada.
[Sense 2, from an association with using pieces of sourdough to leaven bread in the winter.]
- periodicity
- periodic law
- periodic motion
- periodic sentence
- Periodic Table
- periodontal
- periodontally
- periodontia
- periodontic
- periodontical
- periodontics
- periodontist
- perionychium
- periosteal
- periosteous
- periosteum
- periostitic
- periostitis
- periostracum
- periotic
- peripatetic
- peripatus
- peripeteia
- peripetia
- peripety