Nutshell \Nut"shell`\, n. 1. The shell or hard external covering in which the kernel of a nut is inclosed. 2. Hence, a thing of little compass, or of little value. 3. (Zo["o]l.) A shell of the genus Nucula. {To} {be, or lie}, {in a nutshell}, to be within a small compass; to admit of very brief or simple determination or statement. ``The remedy lay in a nutshell.'' --Macaulay.