A FIR tree is a type of data structure used in computer science, particularly in the field of information retrieval and data storage. It is a balanced tree that allows for efficient searching, insertion, and deletion of data. The structure is designed to maintain a sorted order of elements, making it easier to access and manage large datasets. FIR trees are particularly useful in applications where quick access to data is essential, such as databases and file systems. They help optimize performance by reducing the time complexity of operations, ensuring that data can be retrieved or modified swiftly and efficiently.