noun, plural al·to·stra·tus. Meteorology.
- a cloud of a class characterized by a generally uniform gray sheet or layer, lighter in color than nimbostratus and darker than cirrostratus: of medium altitude, about 8000–20,000 feet (2450–6100 meters).
noun plural -ti (-taɪ)
- a layer cloud at an intermediate height of about 2400 to 6000 metres (8000 to 20 000 feet)
Plural altostrati (ăl′tō-străt′ī′)
- A mid-altitude cloud that extends in flat, smooth sheets or layers of varying thickness. Altostratus clouds generally form between 2,000 and 6,100 m (6,560 and 20,000 ft) and often produce long, steady rain showers. See illustration at cloud.