The stratosphere (strato- simply means "layer" or "level") lies above the earth's weather and mostly changes very little. It contains the ozone layer, which shields us from the sun's ultraviolet radiation except where it's been harmed by manmade chemicals.

What does the prefix Strato?

before vowels strat-, word-forming element referring to layers or layering, also stratus clouds, from combining form of Latin stratus "a spreading," from PIE root *stere- "to spread."

What is the root word for stratosphere?

1908, from French stratosphère, literally "sphere of layers," coined by French meteorologist Léon-Philippe Teisserenc de Bort (1855-1913) from Latin stratus "a spreading out" (from past participle stem of sternere "to spread out," from PIE root *stere- "to spread") + French -sphère, as in atmosphère (see sphere).