A nominal variable is a type of categorical variable that can have two or more categories, but there is no intrinsic ordering to the categories. Nominal variables are qualitative in nature and cannot be measured or ordered. They are used to name or label variables without providing numeric values. Examples of nominal variables include gender, hair color, and whether a person owns a Macbook. Nominal variables can be coded with numbers, but the order of the numbers is arbitrary and arithmetic operations cannot be performed on them. Nominal variables are often used in statistical analysis and other mathematical sciences as the foundation of data analysis.