Definition of cumulus in English:

cumulus

noun

Meteorology
  • [mass noun] Cloud forming rounded masses heaped on each other above a flat base at fairly low altitude.

    ‘the high cumulus is breaking up to give a lovely summer evening’
    [count noun] ‘silent, moving, red-tinged cumuli’
    • ‘These types of funnel clouds form out of large cumulus clouds or very weak thunderstorms and normally do not have the energy to reach the ground.’
    • ‘When the air condenses into small, lumpy, low pockets of cloud, this is cumulus.’
    • ‘The first normally is associated with vertical clouds such as cumulus.’
    • ‘The azure sky above was only slightly clouded by the thick cumulus clouds that strayed away from each other, to occasionally cover up the sun's streams of rays.’
    • ‘The basic cloud forms are cumulus, which are heaped clouds; stratus, which are layer clouds; and cirrus, which are wispy.’

Origin

Mid 17th century (denoting a heap or an accumulation): from Latin, heap.

Pronunciation:

cumulus

/ˈkjuːmjʊləs/