outermost
adj.the furthest away from the center or the middle of something. It describes the part that is on the very edge.
adj.situated at the greatest distance from the center or the interior of an object. Often used to describe the outermost layer or boundary of a physical structure.
“The outermost layer of the skin is called the epidermis.”
“The planet Neptune is the outermost planet in our solar system, located farthest from the sun.”
“The architect designed the outermost walls with thick insulation to protect the interior from the extreme temperature fluctuations of the desert climate.”
Usage outermost layer
“Far away from the core is the Sun's outermost layer or corona where the temperature is about 2 million C - it can sometimes go up to 40 million C.”
“For solar scientists, total eclipse images produce crucial data on the corona, the sun’s outermost atmosphere.”
From Middle English uttermost, uttirmest, uttermast, outemast, alteration (due to Middle English outre (“outer”)) of Old English ūtemest, ȳtemest (“outermost”), equivalent to outer + -most. Doublet of uttermost.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.