There are n number of OOPS functionality available in Javascript. Some of the basic OOPS terminologies are namespaces, classes, object, constructor, method and much more. Now I will explain one by one with syntax and definition of these terms.

Namespaces: Namespace is a container which provides developer bunch of functionality in a unique application with a specific name.

// global namespace
var MYAPP = MYAPP || {};

The basic terminology definition of Object-Oriented JavaScript are :

Classes: It is used to define object characteristics.

Property:An object characteristic, such as color.

Method:An object capability.

Constructor: It has the same name as the class containing it. A constructor is called when the instance of an object is created.

Object: An instance of a class is called object.

Now By giving an example I will explain all the points.

var MYAPP = MYAPP || {};

MYAPP.event = {};

// Create container called MYAPP.commonMethod for common method and properties
MYAPP.commonMethod = {
  regExForName: "", // define regex for name validation
  regExForPhone: "", // define regex for phone no validation
  validateName: function(name){
    // Do something with name, you can access regExForName variable
    // using "this.regExForName"
  },
 
  validatePhoneNo: function(phoneNo){
    // do something with phone number
  }
}

// Object together with the method declarations
MYAPP.event = {
    addListener: function(el, type, fn) {
    // code stuff
    },
    removeListener: function(el, type, fn) {
    // code stuff
    },
    getEvent: function(e) {
    // code stuff
    }
  
    // Can add another method and properties
}

// Syntax for Using addListener method:
MYAPP.event.addListener("yourel", "type", callback);

Here In the above example, we can see we have created the namespace MYAPP then we have created a container called MYAPP.commonmethod for common method and property. Then we have define variable for checking validation and then define a function to use all the method.