nutshell
UK: ˈnʌt.ʃel | US: ˈnʌt.ʃel
n. the hard outer covering of a nut
n. (idiomatic) a concise summary or encapsulation (e.g., "in a nutshell")
The word "nutshell" combines "nut" (from Old English hnutu, meaning the seed of a tree) and "shell" (from Old English scell, meaning a hard outer covering). The term literally refers to the protective casing of a nut, but its idiomatic use—to describe something summarized concisely—dates back to the 16th century. The phrase "in a nutshell" likely alludes to the idea of fitting a large idea into a small, compact space, much like a nut's kernel fits inside its shell.
She cracked the nutshell open with a nutcracker.
The report summarized the findings in a nutshell.
"To put it in a nutshell, we need more funding," he said.
The walnut's nutshell was surprisingly tough.
His entire argument was presented in a nutshell.