nutshell

n. 1. The shell or hard external covering in which the kernel of a nut is inclosed. [ 1913 Webster ]

2. Hence, a thing of little compass, or of little value. [ 1913 Webster ]

3. (Zool.) A shell of the genus Nucula. [ 1913 Webster ]

in a nutshell in a summarized and very abbreviated form; -- of statments, descriptions, reports, and other communications; as, to describe the convention in a nutshell. --
To be in a nutshell or
To 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. [ 1913 Webster +PJC ]