A cloud forming rounded masses heaped on each other above a flat base at fairly low altitude.
- ‘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.’
- ‘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.’
- ‘The basic cloud forms are cumulus, which are heaped clouds; stratus, which are layer clouds; and cirrus, which are wispy.’
- ‘The first normally is associated with vertical clouds such as cumulus.’
- ‘When the air condenses into small, lumpy, low pockets of cloud, this is cumulus.’
Mid 17th century (denoting a heap or an accumulation): from Latin, heap.