fungus

noun

fun·​gus ˈfəŋ-gəs 

plural fungi ˈfən-ˌjī  ˈfəŋ-ˌgī  also funguses ˈfəŋ-gə-səz 

often attributive

: any of a kingdom (Fungi) of saprophytic and parasitic spore-producing eukaryotic typically filamentous organisms formerly classified as plants that lack chlorophyll and include molds, rusts, mildews, smuts, mushrooms, and yeasts

Examples of fungus in a Sentence

Recent Examples on the Web

Finally, like mealy bugs, the honeydew secreted by aphids can encourage the growth of sooty mold and fungus. —Jon Vanzile, The Spruce, 30 Jan. 2026

Well before plants and animals, there were fungi. —Big Think, 29 Jan. 2026

Good air circulation helps moisture on leaves and stems dry faster so fungi don't get a chance to get established. —Leanne Potts, Better Homes & Gardens, 28 Jan. 2026

There are two broad approaches; one is based on soil mineral content, while the other is more attentive to the health of soil life in the form of aerobic bacteria and beneficial fungi, especially mycorrhizae. —Joshua Siskin, Oc Register, 24 Jan. 2026

Word History

Etymology

Latin

First Known Use

1527, in the meaning defined above

Phrases Containing fungus

• bracket fungus
• chytrid fungus
• club fungus
• cup fungus
• fungus gnat
• imperfect fungus
• lower fungus
• pore fungus
• sac fungus
• shelf fungus

Rhymes for fungus

• fungous
• tungus

Kids Definition

fungus

noun

fun·​gus ˈfəŋ-gəs 

plural fungi ˈfən-ˌjī  ˈfəŋ-ˌgī  also funguses

1

: any of a kingdom of living things (as molds, rusts, mildews, smuts, and mushrooms) that lack chlorophyll, are parasitic or live on dead or decaying organic matter, and were formerly considered plants

2

: infection with a fungus

fungus adjective

Medical Definition

fungus

noun

fun·​gus ˈfəŋ-gəs 

plural fungi

ˈfən-ˌjī also ˈfəŋ-ˌgī

also funguses ˈfəŋ-gə-səz 

often attributive

1

: any of the kingdom Fungi of saprophytic and parasitic spore-producing eukaryotic typically filamentous organisms formerly classified as plants that lack chlorophyll and include molds, rusts, mildews, smuts, mushrooms, and yeasts

2

: infection with a fungus