What API Means ?

API means - Application Programming Interface

API is a technology to facilitate communication between software applications/devices

API is a set of programming code that enables data transmission from one software/server or product to another

Analogy: In a restaurant you give food order to waiter. He he brings food from kitchen. Here waiter is API, you are client and kitchen is a server

API is simplified way of connecting your application with other applications like Twitter  or Google to get data

APIs open up access to other applications' resources maintaining and security and control 

Use of APIs can save huge time and cost of development