What does (function($) {})(jQuery); mean?

Question

I am just starting out with writing jQuery plugins. I wrote three small plugins but I have been simply copying the line into all my plugins without actually knowing what it

Answer 1

Just small addition to explanation

This structure (function() {})(); is called IIFE (Immediately Invoked Function Expression), it will be executed immediately, when the interpreter will reach this line. So when you're writing these rows:

(function($) {
  // do something
})(jQuery);

this means, that the interpreter will invoke the function immediately, and will pass jQuery as a parameter, which will be used inside the function as $.