AMQP, or Advanced Message Queuing Protocol, is an open standard protocol designed for message-oriented middleware. It enables different applications to communicate with each other by sending messages in a reliable and efficient manner. AMQP supports various messaging patterns, such as point-to-point and publish-subscribe, making it versatile for different use cases. The protocol defines a set of rules for message formatting, queuing, and routing, ensuring that messages are delivered even in the event of network failures. RabbitMQ and Apache Qpid are popular implementations of AMQP, providing developers with tools to build robust messaging systems.