Fourth normal form (4NF) refers to a database normalization technique that helps in improving the integrity and consistency of data within a database. Some synonyms for 4NF include fourth level normalization, fourth degree normalization, and fourth form normalization. This technique is useful in eliminating data redundancy and dependency, thus enhancing data integrity, accuracy, and consistency. Other synonyms include multi-valued dependency normalization and non-loss decomposition normalization. The significance of 4NF lies in its ability to maintain the consistency and reliability of data within a database, which is essential for making informed business decisions and improving organizational efficiency. In conclusion, 4NF is an essential technique in database management and helps in ensuring the accuracy and consistency of data.