cirrus

noun

cir·​rus ˈsir-əs 

plural cirri ˈsir-ˌī 

1

: tendril

2

: a slender usually flexible animal appendage or projection: such as

a

: an arm of a barnacle

b

: a filament of a crinoid

c

: a fused group of cilia functioning like a limb on some protozoans

d

: the male copulatory organ of various invertebrate animals

3

: a high wispy white cloud usually of minute ice crystals formed at altitudes between about 20,000 and 40,000 feet (6,000 and 12,000 meters) see cloud illustration

Examples of cirrus in a Sentence

Recent Examples on the Web

There wasn’t a single cloud in the sky, not even a cirrus wisp or fading contrail. —Ross Andersen, The Atlantic, 11 July 2024

The water vapor and cirrus clouds that planes trail behind them look picturesque, but their warming impact is three times that of carbon. —Liza Featherstone, The New Republic, 28 Dec. 2022

An orographic cirrus cloud formation on the eastern side of the Rocky Mountains, as seen at night by the Suomi NPP satellite on 12/18/13. —Tom Yulsman, Discover Magazine, 20 Dec. 2013

Aside from those brief glimpses through the storm, the cirrus clouds resembled a flat blanket beneath the deep blue sky. —Ian Jamesstaff Writer, Los Angeles Times, 1 Feb. 2023

Word History

Etymology

New Latin, from Latin, curl

First Known Use

1708, in the meaning defined at sense 1

Kids Definition

cirrus

noun

cir·​rus ˈsir-əs 

plural cirri ˈsi(ə)r-ˌī 

: a thin white cloud usually of tiny ice crystals formed at altitudes about 20,000 to 40,000 feet (6,000 to 12,000 meters)

Medical Definition

cirrus

noun

cir·​rus ˈsir-əs 

plural cirri ˈsi(ə)r-ˌī 

: a slender usually flexible animal appendage: as

a

: a fused group of cilia functioning like a limb on some protozoans

b

: the male copulatory organ of some worms