API
From Dikapedia
Application Programming Interface
TL/DR: APIs just allow applications to communicate with each other.
An API is a software intermediary that allows two apps to talk to each other. In other words:
- An API is the messenger that delivers your request to the provider that you're requesting it from and then delivers the response back to you.
- The way for an application to interact with certain system/application/library/etc.
- Integrating link between a third-party platform for applications to access its features and services.
- A publicly available web-based API that returns data, like in JSON or XML.
- An API is NOT a database.
APIs are usually developed in a form consumable a client app.