Mold is the general term given to a coating or discoloration found on the surface of certain materials; it is produced by the growth of a fungus. Mold also refers to the causative organism itself.

A mold is a microfungus (as opposed to the macrofungi, such as mushrooms and toadstools) that feeds on dead organic materials. Taxonomically, the molds belong to a group of true fungi known as the Ascomycotina. The characteristics of the Ascomycotina are that their spores, that is their reproductive propagules (the fungal equivalent of seeds), are produced inside a structure called an ascus (plural asci). The spores are usually developed eight per ascus, but there are many asci per fruiting body (structures used by the fungus to produce and disperse the spores). A fruiting body of the Ascomycotina is properly referred to as an ascomata. Another characteristic of molds is their rapid growth once...