A nutshell is the outer shell of a nut. Most nutshells are inedible and are removed before eating the nut meat inside.
Most nutshells are useful to some extent, depending on the circumstances. Walnut shells can be used for cleaning and polishing, as a filler in dynamite, and as a paint thickening agent. Shells from pecans, almonds, Brazil nuts, acorns, and most other nuts are useful in composting.
Shells can also be used as loose-fill packing material, to protect fragile items in shipping.
The expression "in a nutshell" (of a story, proof, etc.) means "in essence", metaphorically alluding to the fact that the essence of the nut - its edible part - is contained inside its shell. The expression further gave rise to the journalistic term nut graph, short for nutshell paragraph.
A likely source of the phrase may be found in Shakespeare's Hamlet (Act 2, Scene 2) where the title character exclaims: "O God, I could be bounded in a nutshell, and count myself a King of infinite space".
Older uses of this have been reported, too. It is said to have been used by Pliny the Elder. He mentioned in the encyclopedic Naturalis historia a report by Cicero saying that a handwritten version of the Iliad by Homer would have fit in a nut[shell]: „in nuce inclusam Iliadem Homeri carmen in membrana scriptum tradit Cicero“.
- "Walnuts as a filler in dynamite, thickening agent, and polisher.", Wikipedia Walnut Article, accessed November 07, 2010.
- "Composting Nut shells.", GardenWeb, accessed November 07, 2010.
- Ernst Lautenbach: Latein-Deutsch: Zitaten-Lexikon, Quellennachweise, Münster, LIT, 2002, ISBN 3-8258-5652-6, S. 343
- Naturalis historia, 7, 21, 85; Wikisource-Digitalisat
- "How to Compost Peanut Shells", gardenguides.com