Definition of oidium in English:

oidium

noun

  • 1Botany
    A type of fungal spore (conidium) formed by the breaking up of fungal hyphae into cells, especially as produced by powdery mildews.

  • 2[mass noun] A fungal disease affecting vines, caused by a powdery mildew.

    • ‘The effects of phylloxera were first noted in France in 1863, just as the country was recovering from another great scourge of 19th century European viticulture: oidium, or powdery mildew, which was first noted in 1847.’

Origin

Mid 19th century: modern Latin, from Greek ōion egg + the diminutive suffix -idion.

Pronunciation:

oidium

/əʊˈɪdɪəm/