From Middle English myldew, from Old English meledēaw, mildēaw, from Proto-West Germanic *milidauw, from *mili (“honey”) +‎ *dauw (“dew”). Compare West Frisian moaldau, Dutch meeldauw, German Mehltau. More at dew.

• (UK) IPA^(key): /ˈmɪl.djuː/

• Audio (Southern England):

  (file)

• (US) IPA^(key): /ˈmɪl.d(j)u/
• Rhymes: -ɪldjuː, -ɪldu

mildew (countable and uncountable, plural mildews)

1. (phytopathology) A growth of minute powdery or webby fungi, whitish or of different colors, found on various diseased or decaying substances.

• → Catalan: míldiu
• → French: mildiou
• → Portuguese: míldio
• → Spanish: mildiu

mildew (third-person singular simple present mildews, present participle mildewing, simple past and past participle mildewed)

1. (transitive) To taint with mildew.
   • c. 1603–1606, William Shakespeare, “The Tragedie of King Lear”, in Mr. William Shakespeares Comedies, Histories, & Tragedies[…] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, →OCLC, [Act III, scene iv], page 298, column 1:

     Hee giues the Web and the Pin, ſquints the eye, and makes the Hare‐lippe; Mildewes the white Wheate, and hurts the poore Creature of earth.

2. (intransitive) To become tainted with mildew.
   • 1851 November 14, Herman Melville, “The Spouter-Inn”, in Moby-Dick; or, The Whale, 1st American edition, New York, N.Y.: Harper & Brothers; London: Richard Bentley, →OCLC, page 24:

     His bald purplish head now looked for all the world like a mildewed skull.

• mould, mold

mildew

1. alternative form of myldew