a cloud of a class characterized by thin white filaments or narrow bands and a composition of ice crystals: of high altitude, ab. 20,000–40,000 ft. (6000–12,000 m).
b.
a cirriform cloud.
2.
Botany. a tendril.
3.
Zoology.
a.
a filament or slender appendage serving as a foot, tentacle, barbel, etc.
b.
the male copulatory organ of flatworms and various other invertebrates.
Origin: 1700–10; < L: a curl, tuft, plant filament like a tuft of hair
Main Entry: cir·rus Pronunciation: 'sir-&s Function: noun Inflected Form: pluralcir·ri/'si(&)r-"I/ : aslender 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
[sir-uh
s] 
