Full Idea
To define properly means just to exhibit originally the exhaustive concept of a thing within its boundaries
Gist of Idea
Definitions exhibit the exhaustive concept of a thing within its boundaries
Source
Immanuel Kant (Critique of Pure Reason [1781], B755/A727)
Book Reference
Kant,Immanuel: 'Critique of Pure Reason', ed/tr. Guyer,P /Wood,A W [CUO 1998], p.637
A Reaction
There is nothing in the concept of a 'definition' that requires it to be exhaustive, because some things are too vague. Define the 'south' of England. What are the 'boundaries', if the concept could shift in its extension?