mildew

noun mil·dew \ ˈmil-ˌdü , -ˌdyü \

Definition of mildew

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

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mildewy

play \-ē\ adjective

See mildew defined for English-language learners

See mildew defined for kids

Examples of mildew in a Sentence

The basement's damp walls were covered with mildew.

Recent Examples of mildew from the Web

Digging Deeper Peony leaf disease Warm days, cool humid nights — just the weather that powdery mildew loves.

— ellen nibali, baltimoresun.com, "Garden Q&A: Wild violets and oxalis," 29 Aug. 2017
Clean Cannabis Sold by Dow Chemical Co. as Eagle 20, myclobutanil is typically used to combat powdery mildew.

— jack kaskey, Bloomberg.com, "Pot Laced With Pesticides Forces States to Act as EPA Stays Away," 2 Aug. 2017
In basements, photos can be damaged by flooding, humidity, mold and mildew.

— lisa a. flam, Detroit Free Press, "Is your home drowning in old photos? Organizers offer tips," 25 July 2017
A moisture‑resistant rack lets wet towels air out so mildew doesn’t stand a chance, Hagmeyer says.

— martha stewart, star-telegram, "Keep clean and carry on with summertime living," 22 July 2017
In August 2016, the U.S. Housing and Urban Development Office of the Inspector General found infestation, damaged doors and stairs, mold and mildew buildup and health and safety threats related to electrical hazards.

— katherine sayre, NOLA.com, "Central City affordable senior housing proposed in new development," 30 June 2017
Powdery mildew is the most common disease, which first appears as a nickel-sized greyish dusty spot.

— arricca sansone, Country Living, "Everything You Need to Know About Planting Pumpkin Seeds," 29 June 2017
Hybrid introductions of the U.S. Department of Agriculture over the past 40 years have aimed at finding mildew resistance.

— neil sperry, star-telegram.com, "‘Why are my crape myrtles not blooming?’ and other queries on the Southern favorite," 21 June 2017
The space, frigid on a warm evening, smelled of mildew.

— Courant Community, "Dr. Martin Luther King Jr. School Renovation Plan Gets Hartford Board Of Ed Approval," 20 June 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'mildew.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Origin and Etymology of mildew

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

NEW! Time Traveler

First Known Use: 14th century

See Words from the same year

mildew

verb

Definition of mildew

transitive verb

:to affect with or as if with mildew

intransitive verb

:to become affected with mildew

Recent Examples of mildew from the Web

For the past 20 years, my husband, Alex, and I—West Coast transplants and die-hard beach people—have spent a ridiculous amount of money to rent a mildewing summer house on the tip of Long Island.

— rebecca misner, CNT, "For the Ultimate Mediterranean Sailing Trip, Ditch the Captain and Crew," 20 July 2017
Any worn out, or damaged material that is mildewed or dirty.

— sharon hlapcich, Orange County Register, "Race to benefit Anaheim’s adopted Marine unit," 11 May 2017

First Known Use of mildew

1552

MILDEW Defined for English Language Learners

mildew

noun

Definition of mildew for English Language Learners

: a usually white substance that grows on the surface of things in wet, warm conditions

MILDEW Defined for Kids

mildew

noun mil·dew \ ˈmil-ˌdü , -ˌdyü \

Definition of mildew for Students

1 :a thin whitish growth produced by a fungus especially on decaying material or on living plants

2 :a fungus producing mildew

mildew

verb

Definition of mildew for Students

mildewed; mildewing

:to become affected with mildew

Medical Dictionary

mildew

noun mil·dew \ ˈmil-ˌd(y)ü \

medical Definition of mildew

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