What does stratus mean?
Stratus is the name of a low, extensive cloud genus whose clouds usually form a broad, relatively uniform layer across the sky. Stratus clouds often have a flat base and a smooth or gently undulating appearance; they can produce drizzle or light rain and may bring persistent overcast conditions. The term belongs to the formal international system of cloud classification and is used both by meteorologists and in everyday descriptions of dull, low cloud. Its Latin name reflects the idea of something spread or laid out in layers, which closely resembles the way stratus commonly blankets the lower atmosphere. Although other cloud genera are distinguished by features such as vertical development or isolated formation, stratus is particularly characterized by its layered, horizontally spread appearance.
nounA type of low cloud occurring in a broad, usually uniform layer, often with a flat base and accompanied by drizzle or light rain.
- A genus of low cloud forming a widespread, usually uniform layer, commonly with a flat base and sometimes producing drizzle or light rain.
"A bank of stratus rolled in from the coast and concealed the hills for most of the morning."
"Low stratus obscured the airport for much of the morning."
"The meteorologist reported thick stratus extending across the coastal region."
“Stratus clouds” is the clearest and most natural plural in general usage. “Stratuses” is also accepted, particularly in formal or taxonomic contexts.
"Low stratus clouds gathered along the coast before sunrise."
The name comes from a Latin word meaning “spread out,” apt for a cloud that forms a broad, level sheet across the sky.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does stratus come from?
Stratus comes from Latin strātus, the past participle of sternere, meaning “to spread out” or “to lay down.” The Latin word referred to a layer spread over a surface and also gave rise to stratum. English borrowed the term for a cloud layer during the early development of meteorological nomenclature in the 19th century. Related English forms include stratum, stratify, and stratiform, all reflecting the idea of layers or layered arrangement.
How stratus is actually used
In meteorology, the name is normally used in the singular when naming the cloud genus, as in “stratus cloud.” The plural is commonly “stratus clouds” in general writing, although “stratuses” is also standard. As a scientific term, it is commonly italicized in formal cloud classifications.
Easily confused with stratus
Stratus is a genus of cloud, whereas a stratum is a layer or level in a geological, biological, or social system.