Nominal data is a type of categorical data that represents distinct categories without any inherent order. Examples include gender, eye color, and types of fruit. Each category is unique and cannot be ranked or measured in a meaningful way. This data is often used in surveys and research to classify information. For instance, when asking respondents to select their favorite color, the answers can be grouped into categories like red, blue, or green, but one color is not considered better or worse than another.