Meteorology .

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).

a cirriform cloud.

Botany . a tendril.

Zoology .

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

the male copulatory organ of flatworms and various other invertebrates.