SQS is a web service that gives you access to a message queue that can be used to store messages while waiting for the messages to process them. It is a distributed queue system that enables web service applications to quickly and reliably queue messages that one component in the application generates and another consumes.

In other words, a queue is a temporary repository for messages that are awaiting process.

You can also think of SQS as a buffer between two components, producing data and a component consuming data. This means that a queue consumes data. This means that a queue could potentially resolve issues that come about when a producer is producing at a larger rate than what the consumer can handle.