Meaning of the word "outer layer" in English

What does "outer layer" mean in English? Explore the meaning, pronunciation, and specific usage of this word with Lingoland.

outer layer

US /ˈaʊtər ˈleɪər/
UK /ˈaʊtə ˈleɪə/

Noun

the outermost part or covering of something

Example:
The planet's outer layer is composed mainly of rock.
Peel off the outer layer of the onion before chopping.