MAMP stands for Macintosh, Apache, MySQL, and PHP. MAMP is an application you can install on your Mac which allows you to have access to a local PHP server and MySQL server. Essentially, MAMP gives you all of the tools you need to run WordPress on your machine, for development and testing purposes. You can accomplish this in different ways, but the other ways aren’t nearly as simple.
Before you can install MAMP on your Mac, you’ll need to download it from the MAMP website. MAMP requires that your Mac be running Mac OS X 10.6.6 or later.
Once the MAMP download is complete, double-click the MAMP disk image (it should be something like MAMP_2.0.3.dmg), and you should get a MAMP window pop up. Drag the MAMP folder to the Applications folder.
Now that you’ve got MAMP installed on your system, launch MAMP.app
While you’re editing settings, MAMP might prompt you for an administrator password. This is required because MAMP needs to run two processes: mysqld (MySQL) and httpd (Apache), and depending on the settings you set for those processes, you may or may not need to input your password.