Queue
A holding line for work a system will do soon. Jobs wait in the queue until a worker picks them up.
What it tells you about a developer
Queue experience is a scale signal. Small apps never need one. A developer who has used queues has worked on something big enough that the work could not all happen instantly, and has thought about what happens when a job fails partway through.
When an app has more work than it can do instantly, it writes each job to a queue and answers the user right away. Separate programs called workers pull jobs off the queue and run them. Queues absorb traffic spikes and keep slow tasks, like sending ten thousand emails, from blocking the screen. Common tools include RabbitMQ, Amazon SQS, and Kafka.