nutshell
//ˈnʌtˌʃɛl//
Noun
nutshellSingular
nutshellsPlural
1
The hard outer covering or shell of a nut.
She cracked open the nutshell to get to the walnut inside.
2
(idiomatic, in the phrase 'in a nutshell') A very brief or concise summary; the essential facts or points.
In a nutshell, the project was a success.