cirrus
/ˈsɪrəs
/noun (plural cirri /ˈsɪrʌɪ/)
1 [mass noun] Cloud forming wispy filamentous tufted streaks or ‘mare’s tails’ at high altitude (usually 5 to 13 km, 16,500 to 45,000 ft): long strands of high cirrus stretched across the eastern sky [as modifier]: cirrus clouds...
- The basic cloud forms are cumulus, which are heaped clouds; stratus, which are layer clouds; and cirrus, which are wispy.
- In the troposphere, water exists as vapor in air, as liquid droplets in clouds, and as frozen ice particles in high altitude cirrus clouds.
- The formation of wispy cirrus clouds is not a simple matter.
2 Zoology A slender tendril or hair-like filament, such as the appendage of a barnacle, the barbel of a fish, or the intromittent organ of an earthworm.Once the barnacles extended their cirri (fanlike, food-gathering appendages) and started waving them about to collect nutritious particles in the water, the researchers cast a shadow over them with a piece of cardboard....
- Other common elements may include the possession of fixed conical teeth and cirri, or fleshy hair-like projections, on the head.
- The head is often blunt and typically adorned with tentacles or cirri.
2.1 Botany A tendril.
Derivatives
cirrose
cirrous
Origin
Early 18th century (in the sense 'tendril'): from Latin, literally 'a curl'.