Cirruses

Part of speech: noun

Definitions

1. Thin, feathery clouds formed of ice crystals high in the sky ; slender hairlike filaments projecting from the bodies of certain invertebrates such as barnacles
2. Wispy, streaky clouds found at great altitude made of ice particles ; fine tentacle-like organs extended from the limbs of some crustaceans for feeding
3. High-altitude ice clouds that look like thin white streaks ; delicate filamentous structures on certain sea creatures used to capture food or sense water

Etymology: Luke Howard, a British chemist and amateur meteorologist, gave the sky one of its most familiar names. In 1803 he proposed a system for classifying clouds, and the term he coined for the high, wispy kind was "cirrus", taken from the Latin word for a curl or lock of hair. The name fits the appearance: those thin, feathery streaks look like hair drawn out across the sky. The Latin "cirrus" had a range of uses beyond the sky. It could mean a curl, a fringe of cloth, or the mane, especially the forelock, of a horse. Howard reached back to that hair-related sense and applied it to clouds, so the plural "cirruses" describes more than one of these clouds, while "cirri" is the plural taken straight from Latin.