CIRRUS

noun (plural cirri) Etymology: New Latin, from Latin, curl Date: 1708 tendril , a slender usually flexible animal appendage or projection: as, an arm of a barnacle, a filament of a crinoid, a fused group of cilia functioning like a limb on some protozoans, the male copulatory organ of various invertebrate animals, a high wispy white cloud usually of minute ice crystals formed at altitudes between about 20,000 and 40,000 feet (6,000 and 12,000 meters)