In jQuery, there are mainly two namespaces –
1) jQuery.fn namespace ( $.fn namespace ) and
2) jQuery namespace ($ namespace )
$ sign is an alias of jQuery (also known as Hungarian notation). This $ can be returned to its original i.e. jQuery using jQuery.noConflict(). This is used when $ variable/ sign is being used by some other library. Also sometime, it is used to handle different versions of jQuery on the same page.
Each namespace has its own context.
$ Namespace is mainly focused on utilities functions and its methods are known as core methods. These core methods do not work with selections.
Ex. $.proxy(), $.each(), $.extend(), $.inArray() etc.
$.trim(' c-sharpcorner.com ');
$.fn namespace (also knowns as jQuery prototype) focus on methods that works on jQuery objects and these methods are referred as jQuery object methods. All methods used on this fashion or jQuery Object Methods - $(expressionForSelection).allMethods()
Another thing is that jQuery object method returns jQuery object while core methods not(also its return type is differ on case to case).