What is a distributed messaging system? Specifically what is 'distributed' in it?

Question

It is ubiquitously mentioned that - 'Celery is an asynchronous task queue/job queue based on distributed message passing'.Though I know how to use Celery workers and all.But deep down I dont understand the real importance and meaning of distributed messaging passing and role of task queue in it.

I have surfed much of the internet but nowhere is the clear explanation of the definition word by word.It is just always mentioned as a fact.

Can someone please here spare his/her time to explain all the importance of the terms with some relevant examples?

Sorry if this question looks trivial to most of the people but for me solution to this will go long way in understanding how things work.

Thanks.

Answer 1

To put it very simply "distributed" means that the work is distributed among many workers.

distribute
dɪˈstrɪbjuːt,ˈdɪstrɪbjuːt/Submit
verb
past tense: distributed; past participle: distributed
1.
give a share or a unit of (something) to each of a number of recipients.

when you run a task celery puts it on a queue, messages are passed to the workers, one of them runs the task.