What are providers in general and what are service providers in laravel? [duplicate]

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• Laravel 4 - when to use service providers? 3 answers

I've been learnig laravel framework. I don't quite get what are providers used for. As far as I can understand it is a kind of design pattern. Could you explain it in simple words. Also, it would be interesting to find out the difference between Angularjs providers and Laravel providers.

PS. I am not cofusing angularjs and laravel, I just want to get some comparison or simple symbolic description of what a provider is.