A priority queue is a special type of data structure that stores elements with associated priorities. In a priority queue, elements with higher priority are served before those with lower priority, regardless of their order in the queue. This makes priority queues useful in scenarios like scheduling tasks or managing resources, where certain tasks need to be addressed before others. Priority queues can be implemented using various data structures, such as heaps, arrays, or linked lists. The most common implementation is the binary heap, which allows for efficient insertion and removal of elements based on their priority. This efficiency makes priority queues essential in algorithms like Dijkstra's for finding the shortest path in graphs.