Fermented dough used for making bread, biscuits flapjacks, etc.

this bread is fermented and steamed and then baked

a leaven of dough in which fermentation is active; used by pioneers for making bread

leavened with a small amount of fermented dough; "sourdough bread"

A type of bread that has been leavened using both wild yeasts and lactobacili rather than the specific lab cultured yeasts of commercial breads. It may or may not be sour, depending on which yeasts/bacterium cultures are used.

Sourdough is a symbiotic culture of lactobacilli and yeasts used to leaven bread. Sourdough bread has a distinctive taste, due mainly to the lactic acid and acetic acid produced by the lactobacilli.