Sourdough (noun)

1. A type of bread made from a fermented dough that contains wild yeast and lactobacilli.
2. A mixture of flour and water that is used to ferment and leaven bread dough.

Origin:

From french pain souder, from pain ("bread") + souder ("to leave.n")

Examples:

1. Sourdough bread is known for its tangy flavor and chewy texture.
2. Sourdough is a traditional bread that has been made for centuries.
3. Sourdough bread is made using a sourdough starter instead of commercial yeast.
4. Sourdough is a natural leavening agent that is used to make bread rise.
5. The sourdough bread is delicious with a little bit of butter and jam.