A module is a container for different part of an App which includes controller, services, filters, directives and many more.

We can also say that it is a collection of controllers, filters, services, directives, etc.

Syntax for creating a module:

var demoModule = angular.module('demoModule', []);

In this, angular.module is a global for creating and retrieving the angular modules.

In this, [] parameter is used to define the dependent modules.

Syntax for adding the controllers, directives and services in the module:

For Services:

demoModule.service('demoService', function(){...});

For Directives:

demoModule.directive("demoDirective", function(){...});

For Controller:

demoModule.controller("demoCtrl", function($scope) {...});

Hope this will help you with module.