cirrus

American  

[sir-uhs] / ˈsɪr əs /

noun

• cirrus,
  plural
• cirri
  plural

1. Meteorology.

   1. a cloud of a class characterized by thin white filaments or narrow bands and a composition of ice crystals: of high altitude, about 20,000–40,000 feet (6000–12,000 meters).

   2. a cirriform cloud.

2. Botany. a tendril.

3. Zoology.

   1. a filament or slender appendage serving as a foot, tentacle, barbel, etc.

   2. the male copulatory organ of flatworms and various other invertebrates.

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cirrus British  

/ ˈsɪrəs /

noun

1. meteorol a thin wispy fibrous cloud at high altitudes, composed of ice particles

2. a plant tendril or similar part

3. zoology

   1. a slender tentacle or filament in barnacles and other marine invertebrates

   2. a hairlike structure in other animals, such as a filament on the appendage of an insect or a barbel of a fish

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cirrus Scientific  

/ sîr′əs /

• cirri
  plural

1. A high-altitude cloud composed of feathery white patches or bands of ice crystals. Cirrus clouds generally form between 6,100 and 12,200 m (20,000 and 40,000 ft).

2. See illustration at cloud

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Other Word Forms

Noun Inflected Forms

• cirri
  plural
• cirrus
  plural

Etymology

Origin of cirrus

1700–10; < Latin: a curl, tuft, plant filament like a tuft of hair

Example Sentences

See Examples For:

cirrus cirri

The most likely explanation is the presence of thick but uneven water ice clouds, similar to cirrus clouds high in Earth's atmosphere -- an unexpected complication.

From Science Daily ● Apr. 22, 2026

Wind shear can occur in wispy cirrus clouds or even in clear air near thunderstorms, as differences in temperature and pressure create powerful currents of fast-moving air.

From Seattle Times ● May 21, 2024

The remaining, thinner cirrus clouds would allow more long-wave radiation emanating from Earth to escape to space.

From Scientific American ● Sep. 20, 2023

Brilliant red, orange and scarlet sunsets often take place in the presence of higher cirrus or altocumulus clouds instead of low-level clouds such as stratus or stratocumulus.

From Washington Post ● Apr. 13, 2023

He looked at the sky and saw the white cumulus built like friendly piles of ice cream and high above were the thin feathers of the cirrus against the high September sky.

From "The Old Man and The Sea" by Ernest Hemingway

In some specimens well preserved in spirits, the sack and cirri were purplish-brown or lead-colour, tinted with dirty green, or orange, or bright yellow, or brick-red.

From A Monograph on the Sub-class Cirripedia With Figures of all the Species. by Charles Darwin

Pedicels of the first four cirri, caudal appendages, penis, the two posterior thoracic segments, the segments of the cirri, and the trophi, clouded, banded, or spotted, with blackish purple.

From A Monograph on the Sub-class Cirripedia With Figures of all the Species. by Charles Darwin

This species agrees with P. elegans, in the presence of the singular elbowed teeth, on some of the spines in the first three pairs of cirri.

From A Monograph on the Sub-class Cirripedia With Figures of all the Species. by Charles Darwin

Occasionally the storm center is too far to the south or north to cause rains at your locality, but the cirri bank up on the horizon and their lacework covers the sky.

From Reading the Weather by Thomas Morris Longstreth

On Tuesday this gentleman reports his detection of some "cirri," and he kindly writes to the Times to give the world the benefit of the discovery.

From Punch - Volume 25 (Jul-Dec 1853) by Various