dequeued

Dequeued is the past participle form of dequeue, meaning to remove an element from a queue. In everyday language, to be dequeued means to have left the line or sequence as items are processed in order. The term is used across computing and information processing to describe the action of taking the next item in line for handling.

In computing, dequeue is an operation that retrieves and removes the element at the front of a queue, which is typically a first-in, first-out data structure. The operation returns the item and updates the queue length. If the queue is empty, implementations may block until a new item arrives, return a special value, or raise an exception, depending on the language or framework.

In distributed systems and messaging, dequeuing refers to a consumer taking a message from a queue for processing. Acknowledgments, retries, and dead-letter queues are common aspects of this workflow; the exact semantics depend on the system—ranging from at-least-once to exactly-once processing guarantees. Dequeued messages are often removed from the active queue upon successful processing, though some designs may retain them for auditing or replay purposes.

Etymology-wise, the term derives from queue, meaning a line of items, with dequeued items being those removed from the front of the line. The concept is widely used in queues for tasks, events, or messages, and is paired conceptually with enqueue, the operation that adds items to the queue.