cir·rus 
(sîrəs)
(sîrəs)n. pl. cir·ri (sîrī′)
1. A high-altitude cloud composed of narrow bands or patches of thin, generally white, fleecy parts.
2. Biology
a. A tendril.
b. A slender flexible appendage, such as a tuft of fused cilia of certain protozoans or one of the feathery appendages of a barnacle.
[Latin, curl of hair.]
cirrus