Categorical variable
In statistics , the following types of variables are called categorical variables :
 nominal scaled variables
 ordinal scaled variables

metric variables that have only a few characteristics .
Some authors include scale variables in the case of a few forms or categorization is not the categorical variables. The narrow definition of the term “categorical variable” then only includes nominally and ordinally scaled variables.  Metric variables that have been categorized (example: variable “income” with the categories “500–999 €”, “1000–1499 €” etc.)
See also
 Cardinal variable or metric variable
 Scale level
literature
 Ludwig Fahrmeir , Rita artist, Iris Pigeot , Gerhard Tutz : Statistics. The way to data analysis. 8., revised. and additional edition. Springer Spectrum, Berlin / Heidelberg 2016, ISBN 9783662503713