nutshell

/ˈnʌtˌʃɛl/
noun
  1. The hard outer covering of a nut.
    • She cracked the nutshell with a small hammer to get the walnut inside.
    • The squirrel chewed through the nutshell to reach the kernel.
    • Some nutshells are so tough you need a special tool to open them.
  2. A very small, compact space or container.
    • The inventor built a working computer inside a nutshell.
    • Their tiny apartment was a nutshell of a home, but they loved it.
    • He lived in a nutshell of a room with just a bed and a desk.
Synonyms
idiom
  1. In a nutshell: In a very brief and simple way; summarizing the main point.
    • In a nutshell, we need to finish the project by Friday.
    • The teacher explained the theory in a nutshell so everyone could understand.
    • In a nutshell, the movie is about a robot who learns to feel emotions.