Other forms: strati
A low, flat cloud is called a stratus. When the sky is full of stratus clouds, it can make the day feel gray and dull.
Stratus can be used as a noun or an adjective: "I can't see the moon—there are too many stratus clouds tonight." Strati are characterized by their dense haziness. They are basically fog that sits low in the atmosphere, occasionally releasing small amounts of rain or snow. Sometimes they're called "high fog." In Latin, stratus means "a spreading."