cirrus

American  

[sir-uhs] / ˈsɪr əs /

noun

plural

cirrus, cirri

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.

---

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

---

cirrus Scientific  

/ sîr′əs /

plural

cirri

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

---

Etymology

Origin of cirrus

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

Example Sentences

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

Aside from those brief glimpses through the storm, the cirrus clouds resembled a flat blanket beneath the deep blue sky.

From Los Angeles Times • Feb. 1, 2023

Enjoy it while you can: In a few million years, the nebula will be gone, evaporated by its fierce stellar progeny like a fleecy windblown cirrus cloud on a summer afternoon,

From New York Times • Oct. 19, 2022

It was still clear, but a thin, wispy scum of cirrus had spread across the upper atmosphere, and a dark line of squalls was visible just above the southwestern horizon.

From "Into the Wild" by Jon Krakauer