circumscription

noun4

1. •
   The act of circumscribing or the quality of being circumscribed.
2. •
   The definition of what does and does not belong to a given taxon, from a particular taxonomic viewpoint or taxonomic system.

   • The circumscription in the APG system of the family Malvaceae includes the former families Bombacaceae, Sterculiaceae and Tiliaceae.
3. •
   Anything that circumscribes or a circumscribed area.
4. •
   An electoral district; used often in texts treating electoral systems in Romance countries.