sourdough

sourdough · noun¹

1. Middle English · inherited fromsour dogh
2. English todaysourdough

From Middle English sour dogh, equivalent to sour + dough. Compare Saterland Frisian Suurdee (“sourdough”), Dutch zuurdeeg (“sourdough”), Low German Suurdeeg (“sourdough”), German Sauerteig (“sourdough”), Danish surdej (“sourdough”), Swedish surdeg (“sourdough”), Icelandic súrdeig (“sourdough”). The senses pertaining to California, Alaska and the Yukon derive from the distinctive pouches of bread starter (starter dough used to make sourdough) worn on a belt or around the neck by experienced prospectors during the Klondike Gold Rush and California Gold Rush.

Sourdough · noun²

From sourdough.

First known use, by meaning

• from 14th c. A type of bread dough leavened with yeast and lactobacilli that produce acids giving a sour taste.
• from 1898 An old-timer, especially in Alaska.