yeast

Definition of yeast

yeast (yeest): A type of microorganism that is found almost everywhere, including inside the body. There are many different types of yeast. Some types are used to make foods, such as bread, cheese, and alcoholic drinks. Small amounts of a certain type of yeast normally live on the skin and in some parts of the body, such as the mouth, throat, and vagina. Yeast are a type of fungus.

Source: NCI Dictionary of Cancer Terms