A Fibonacci heap is a type of data structure that supports a collection of trees, which are used to implement a priority queue. It allows for efficient merging of heaps and provides fast operations for inserting elements and decreasing keys. The structure is named after the Fibonacci sequence, as its amortized time complexity for certain operations is based on this mathematical concept. One of the key advantages of a Fibonacci heap is its ability to perform operations like deleting the minimum and decreasing key in constant time on average. This makes it particularly useful in algorithms like Dijkstra's and Prim's for graph processing, where efficient priority queue operations are essential.