A Message Queue (MQ) is a communication method used in microservices where services exchange data asynchronously through messages. A producer (sender) puts messages into a queue, and consumers (receivers) process those messages.

Aggregate Root is a central concept in Domain-Driven Design (DDD). It acts as the entry point to a group of related entities, ensuring consistency and enforcing business rules.

MediatR is a simple, lightweight library that facilitates the Mediator design pattern in C#. In the context of Microservices, MediatR acts as an in-memory message bus that allows decoupled communication between components such as request handlers and command handlers. Instead of components communicating directly with each other, they communicate through MediatR, which routes the message (request) to the appropriate handler.