Webster Dictionary(0.00 / 0 votes)Rate this definition: 1  Cousin(noun) one collaterally related more remotely than a brother or sister; especially, the son or daughter of an uncle or aunt. 2  Cousin(noun) a title formerly given by a king to a nobleman, particularly to those of the council. 3  Cousin(noun) allied; akin.
As everyone has explained MSMQ is used as a queue for messages. Messages can be wrapper for actual data, object and anything that you can serialize and send across the wire. MSMQ has it's own limitations. MSMQ 1.0 and MSMQ 2.0 had a 4MB message limit. This restriction was lifted off with MSMQ 3.0.
RabbitMQ is a server software implementation of AMQP (Advanced Message Queueing Protocol) that can be used by implementing various AMQP client libraries in different programming languages. A summary of what is would be: 1  RabbitMQ is a server that listens to connections in an open socket (for example like Apache or Nginx does in port 80, or like Tomcat does in port 8080) 2  RabbitMQ implements AMQP and so will behave in order to fulfill that protocol.