systematics

Short definition from Wiktionary

Noun

1. 1
   The study of classification systems and nomenclature.
2. 2
   The classification system of a branch of science, especially the classification of organisms in biology.
3. 3
   A branch of Christian theology that formulates an orderly, rational, and coherent account of Christian beliefs. It comprises dogmatics, ethics and philosophy of religion.
4. 4
   The place where legal provisions stand as relevant for their interpretation.