noun.
Any of numerous fungi of the division Ascomycota, characterized by the presence of haploid spores formed within an ascus, and including truffles, morels, and many food molds.
The Century Dictionary and Cyclopedia
noun.
Any member of the class Ascomycetes.
the GNU version of the Collaborative International Dictionary of English
noun.
any fungus of the class Ascomycetes (or subdivision Ascomycota) in which the spores are formed inside an ascus.