mildew

1 of 2

noun

mil·​dew ˈmil-ˌdü 

-ˌdyü

1

a

: a superficial usually whitish growth produced especially on organic matter or living plants by fungi (as of the families Erysiphaceae and Peronosporaceae)

b

: a fungus producing mildew

2

: a discoloration caused by fungi

mildewy

ˈmil-ˌdü-ē 

-ˌdyü-

adjective

mildew

2 of 2

verb

mildewed; mildewing; mildews

transitive verb

: to affect with or as if with mildew

intransitive verb

: to become affected with mildew

Examples of mildew in a Sentence

Noun

The basement's damp walls were covered with mildew.

Recent Examples on the Web

Noun

To mitigate the buildup of hair, soap scum, mildew, and more, frequent cleaning is essential. — Kate Van Pelt, The Spruce, 6 Sep. 2026

How To Remove Lingering Odors or Mildew Smells To tackle lingering odors or mildew smells, try adding one cup of white vinegar to the wash cycle, which helps break down odor-causing bacteria and leaves your bath mat smelling fresh. — Daley Quinn, Southern Living, 4 Sep. 2026

Verb

Linens And Towels Sheets and blankets should be stored outside the bathroom when possible, as should bath towels because all are vulnerable to mildewing. — Hallie Milstein, Southern Living, 17 June 2026

Wandering through the winding streets and mildewing apartments of the medieval Tuscan city, Leonardo becomes the quintessential teenage romantic, both bursting with youthful promise and corroding from adolescent alienation. — Patrick Brzeski, The Hollywood Reporter, 2 Sep. 2024

Word History

Etymology

Noun

Middle English, from Old English meledēaw honeydew; akin to Old High German militou honeydew

First Known Use

Noun

14th century, in the meaning defined at sense 1a

Verb

1552, in the meaning defined at transitive sense

Phrases Containing mildew

• downy mildew
• powdery mildew

Rhymes for mildew

• accrue
• ado
• ainu
• aircrew
• airscrew
• anew
• askew
• baboo
• babu
• bamboo
• beaucoup
• bijou

Kids Definition

mildew

1 of 2 noun

mil·​dew ˈmil-ˌd(y)ü 

: a usually whitish growth produced on decaying material or living plants by fungi

also : a fungus producing mildew

mildewy

-ˌd(y)ü-ē 

adjective

mildew

2 of 2 verb

: to affect with or become affected with mildew

Medical Definition

mildew

noun

mil·​dew ˈmil-ˌd(y)ü 

1

: a superficial usually whitish growth produced especially on organic matter or living plants by fungi (as of the families Erysiphaceae and Peronosporaceae)

2

: a fungus producing mildew