Yeast definition

(1) A type of unicellular, nonfilamentous fungus that resembles bacterial colonies when grown in culture. (2) A term sometimes used to denote the unicellular form of pathogenic fungi. (Alcamo’s Fundamentals of Microbiology)

The single-celled growth form of various fungi. (Brock Biology of Microorganisms)

Single-celled, budding fungi. (Foundation in Microbiology by Talaro and Chess)

Nonfilamentous, unicellular fungi. (Microbiology: An Introduction by Tortora, Funke, and Case)

A unicellular, uninuclear fungus that reproduces either asexually by budding or fission, or sexually through spore formation. (Prescott’s Microbiology)