I&#39;m learning the messaging system and got confused by those terminology. 

All the messaging system below provides loose coupling between services with different sets of features.

`queue` - FIFO, pulling mechanism, 1 consumer each queue but any number of producers?

`message bus` - pub/sub model, any number of consumers with any number of producers processing messages? Is `Azure Service Bus` an implementation of `message bus`? 

`event bus` - pub/sub model, any number of consumers with any number of producers processing events? 

Do people use `message bus` and `event bus` interchangeably as far as terminology goes?

What are the difference between events and messages? Are those just synonyms in this context? 

`event hub` - pub/sub model, partition, replay, consumers can store events in external storage or close to real-time data analysis. What exactly is event hub? 

`event grid` - it can be used as a downstream service of event hub. What does it exactly do that `event hub` doesn&#39;t do? 

Can someone provide some historical context as how each technology evolve to another each tied with some practical use cases?

I&#39;ve found [message bus vs. message queue][1] helpful


  [1]: https://stackoverflow.com/questions/57345003/message-bus-and-message-queue-understanding

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Message bus vs. Service bus vs. Event hub vs Event grid