Is MAMP relatively similar to XAMPP?

MAMP stands for Mac, Apache, MySQL, PHP

It is an adaptation of the phrase "LAMP stack" which is Linux, Apache, MySQL, PHP.

OS X has Apache and PHP built in.  To turn on Apache, check Web Sharing in the Sharing panel of System Preferences.

To turn on PHP, uncomment a line in the file /etc/apache2/httpd.conf

#LoadModule php5_module libexec/apache2/

LoadModule php5_module libexec/apache2/

For MySQL, install the package manager Homebrew, and then at the terminal type:

brew install mysql

It's that easy!