The term 'Cirrostratus' (12 letters) is a type of cloud that is thin, high, and often wispy. It is composed of ice crystals and is usually seen in the form of a sheet or veil. Cirrostratus clouds are typically found at altitudes of 18, 000 to 40, 000 feet and can sometimes produce halos around the sun or moon. They are often associated with the approach of a warm front and can indicate the possibility of rain or snow.