Definition: Statistical category
UN metadata terminology
(1) Fundamental form, defined by statistical methodology, to which a particular object of statistical observation may belong.
(2) Attribute which describes the basic subject-matter division of the statistical information system into homogeneous classes.
Economic Commission for Europe of the United Nations (UNECE), "Terminology on Statistical Metadata", Conference of European Statisticians Statistical Standards and Studies, No. 53, Geneva, 2000