Part of the system of cloud classification, which subdivides the cloud genera according to transparency and the arrangement of cloud elements. Cloud varieties are: duplicatus, intortus, lacunosus, opacus, perlucidus, radiatus, translucidus, undulatus, and vertebratus. The standard abbreviations consist of two letters. To describe a specific cloud, none, one, or more of the terms may be applied to an individual cloud genus. See also cloud species.
Subjects: Meteorology and Climatology.