[sir-oh-strey-tuh
s, -strat-uhs] 
| a cloud of a class characterized by a composition of ice crystals and often by the production of halo phenomena and appearing as a whitish and usually somewhat fibrous veil, often covering the whole sky and sometimes so thin as to be hardly discernible: of high altitude, ab. 20,000–40,000 ft. (6000–12,000 m). |
| cirrostratus (sîr'ō-strāt'əs) Pronunciation Key
Plural cirrostrati (sîr'ō-strāt'ī') A thin, hazy, high-altitude cloud composed of ice crystals, often covering the sky in sheets and producing a halo effect around the sun. Cirrostratus clouds generally form between 6,100 and 12,200 m (20,000 and 40,000 ft). See illustration at cloud. |