Definition of "stratus" [stra•tus]

• A low-altitude cloud formation consisting of a horizontal layer of gray clouds. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Most likely, it was one of the 10 great species of clouds, beginning with low- altitude cumulus ("cotton-wool puffs"), stratocumulus ("a low layer or patch of cloud") and stratus (a "gray overcast layer")."
• "But the sky ... beautiful layers of cloud: cirrus, cumulus, stratus lying in runs from horizon to horizon."
• "I kept to my hands and knees, like a little drunk myself, creeping down the hallway under the stratus cloud of smoke, under the radar, until I found the door with the dark stairs going down."