Altostratus cloud is a type of thin and gray cloud that usually covers the sky. It is formed when warm and moist air rises and condenses at high altitudes. This cloud type is often associated with dull and overcast weather conditions, and it can bring light rain or drizzle. There are a few synonyms that describe this type of cloud. A common synonym for altostratus cloud is "layer cloud," which refers to its flat and even appearance. Another synonym is "thin nimbostratus cloud," which emphasizes its potential to produce light precipitation. Lastly, "stratus clouds at intermediate altitudes" is another way to describe altostratus clouds based on their height in the atmosphere.