Queue is an Abstract Data Type used in programming languages.

flowchart LR
    Enqueue["enqueue new item"] --> Back["back"]
    Back --> B["B"]
    B --> A["A"]
    A --> Front["front / dequeue"]

Anki

id: queue-definition deck: Computer Science::Data Structures tags: data-structures queue

Q: In a queue, which item is removed first? A: The item that has been waiting the longest.

id: queue-fifo deck: Computer Science::Data Structures tags: data-structures queue

Q: What everyday situation behaves like a queue? A: A line of people waiting for service: the first person in line is served first.