a variable whose values indicate a category to which an observation or an object belongs; may be nominal (e.g. eye colour), ordinal (e.g. low, medium, high), or cyclical (e.g. Monday, Tuesday, ... Sunday).
also called qualitative variable A variable whose possible values are one of a number of categories. Although the values may be represented by numeric codes, the numbers are not thought of as measured or counted quantities. cf. quantitative variable.
A categorical variable groups items into pre-defined discrete, non-continuous classes (male, female), (board certified, not board certified). Categories may reflect a natural order, in which case they are called ordinal (cancer stage: I, II, III, or IV), (hospitals rankings: good, better, best).
A piece of information that can be put in a single category, instead of being given a number: for example, the information about whether a person owns a car or about whether the person belongs to a certain race can be put in the category of “yes” or the category of “no.