mildew

Old English meledēaw (“honeydew”) (compare West Frisian moaldau, Dutch meeldauw, German Mehltau), from Proto-Germanic *milidawwaz: compound of *mili (“honey”) + *dawwō (“dew”). More at dew.

• (UK) IPA^(key): /ˈmɪl.djuː/
• (US) IPA^(key): /ˈmɪl.d(j)u/

mildew (uncountable)

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

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

1. (transitive) To taint with mildew.
   • 1605, The Tragedy of King Lear, William Shakespeare, act 3 scene 4

     He […] mildews the white wheat.

2. (intransitive) To become tainted with mildew.
   • 1851, Herman Melville, Moby Dick, chapter 3

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

• mould, mold