What is the function( factory ) pattern for in JS plugins? [duplicate]

I’m seeing a lot of Javascript plugins utilizing a pattern like the one below in the beginning of the main plugin script.

I’ve tried looking up the Internet but couldn’t find any explanation and I don’t have any idea why this is needed.

Excerpt from Datatables:

(function( factory ) {
    "use strict";

    if ( typeof define === 'function' && define.amd ) {
        // AMD
        define( ['jquery'], function ( $ ) {
            return factory( $, window, document );
        } );
    }
    else if ( typeof exports === 'object' ) {
        // CommonJS
        module.exports = function (root, $) {
            if ( ! root ) {
                // CommonJS environments without a window global must pass a
                // root. This will give an error otherwise
                root = window;
            }

            if ( ! $ ) {
                $ = typeof window !== 'undefined' ? // jQuery's factory checks for a global window
                    require('jquery') :
                    require('jquery')( root );
            }

            return factory( $, root, root.document );
        };
    }
    else {
        // Browser
        factory( jQuery, window, document );
    }
}
(function( $, window, document, undefined )
...

Excerpt from Slick.js

;(function(factory) {
    'use strict';
    if (typeof define === 'function' && define.amd) {
        define(['jquery'], factory);
    } else if (typeof exports !== 'undefined') {
        module.exports = factory(require('jquery'));
    } else {
        factory(jQuery);
    }

}(function($) {
...