API centric application or REST or Web service Where to start

Question

BRIEF:

I am working on a web application, we decide to make some major. We did some researches and we found this tutorial that talks about "Creating api centric application".

we found the topic is very useful to us as we need in the near future to make an android app.

WE STARTED WITH:

Doing some searches starting from this query "api centric application" and we found these two topics related to that query:

1. REST
2. WEB SERVICE

WHAT WE WANT TO KNOW:

1. What is the difference between these terms "API centric application", "REST", "Web Service"

2. Is Rest an alternative way of Web service?

3. Is API Centric Application an approach of REST?

4. Is Web Service the parent of all this terms?

Do i need to produce some other information in order to this question be eligible for policy.

Answer 1

After study all these types i found that :

A Web Service is a type of API, and all web-services must be API but not all API's must be web-services, The REST is a new concept of writing web-services and Web services written by apply REST Architectural concept are called RESTful web services

So my focus will be on changing my application to be API centric application by using REST Web service as this practice