Nosology is the branch of medicine that deals with the Classification of diseases.
It can also be applied to the collection of evidence relating to whether a particular condition should be regarded as a disease entity.
In Psychology, Nosologies refer to efforts to classify psychiatric disorders into descriptive categories.
It is also called Nosonomy, or Nosotaxy.
Other /More definition:
nosology refers to classification and naming system for medical and psychological phenomena.
Lexicon of Psychology - Terms, Treatments, Biographies,