High altitude ice clouds with a very thin wispy appearance.
• (a.) Formed like a cirrus or tendril; -- said of appendages of both animals and plants.
High altitude ice clouds with a very thin wispy appearance.
Cir'ri·form adjective [ Cirrus + -form .] (Biol.) Formed like a cirrus or tendril; -- said of appendages of both animals and plants. 
of or pertaining to clouds composed of ice crystals, as cirrus, cirrostratus, and cirrocumulus clouds.