/sir"euhs/ , n. , pl. cirrus for 1, cirri /sir"uy/ for 2, 3.
1. Meteorol.
a. 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. Bot. a tendril.
3. Zool.
a. a filament or slender appendage serving as a foot, tentacle, barbel, etc.
b. the male copulatory organ of flatworms and various other invertebrates.
[ 1700-10; ]