A type-two fuzzy set is a unique concept that is used in various fields such as image processing, artificial intelligence, and machine learning. It is a generalization of the conventional type-one fuzzy set and includes a second level of fuzziness. Some of the synonyms for the term "type-two fuzzy set" include interval type-2 fuzzy set, generalized type-2 fuzzy set, granular computing type-2 fuzzy set, two-tuple fuzzy set, and hybrid fuzzy set. Each of these synonyms indicates a specific aspect of the type-two fuzzy set, and depending on the context, one might be used over the other. With their ability to capture greater uncertainty, type-two fuzzy sets have become increasingly important in recent years, and their use is likely to continue growing in various fields.