A local server, in its simplest definition, is a web server that exists on a local system, such as your desktop computer, and is not accessible by the world wide web. It’s a common practice in web development as a whole, but it plays an especially vital role in WordPress development due to its ability to allow you to test a variety of different components on a WordPress site without having to pay for a live server or affect the live version of a site. WordPress contains a variety of different components that allow it to behave and perform the way it does. A typical WordPress setup includes an operating system for the server application to run on (Windows, OS X or Linux), a web server application (Apache), a database management system (MySQL or MariaDB) and a programming language (PHP). This is why you’ll see many applications se these components as acronyms for their names:
MAMP
My Apache MySQL PHP
LAMP
Linux Apache MySQL PHP (or Python or Perl)
XAMPP
X (Cross Platform) Apache MariaDB PHP Perl
We’re going to learn how to create a local test server for WordPress using MAMP in this post, but first, let’s start with why developers use test servers and why you specifically
Source: https://managewp.org/articles/15859/how-to-create-a-local-test-server-for-wordpress-using-mamp
Willie Chiu's Blog 