- Meteorology.
- 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).
- a cirriform cloud.
- 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.
- a thin wispy fibrous cloud at high altitudes, composed of ice particles
- a plant tendril or similar part
- zoology
- a slender tentacle or filament in barnacles and other marine invertebrates
- a hairlike structure in other animals, such as a filament on the appendage of an insect or a barbel of a fish
