Fungi (singular: fungus) are a kingdom of usually multicellular eukaryotic organisms that are heterotrophs (cannot make their own food) and have important roles in nutrient cycling in an ecosystem.

Kingdom Fungi includes a diverse group of mainly multicellular organisms that possess traits of both plants and animals. Fungi examples include mushrooms, molds and yeasts for making bread. Fungi can be beneficial by breaking down decayed matter or harmful by causing parasitic infections.

Fungus, any of about 144,000 known species of organisms of the kingdom Fungi, including yeasts, mildews, molds, and mushrooms. Fungi are some of the most widely distributed organisms on Earth and are of great environmental and medical importance.

The fungi kingdom is more similar to the animal kingdom than the plant kingdom. The word "fungus" is a Latin word meaning "mushroom". It is estimated that there are at least 1.5 million different species of fungi. The top of a mushroom is called the cap. The small plates under the cap are called gills.

Basidiomycota, large and diverse phylum of fungi (kingdom Fungi) that includes jelly and shelf fungi; mushrooms, puffballs, and stinkhorns; certain yeasts; and the rusts and smuts. Basidiomycota are typically filamentous fungi composed of hyphae.