cPanel is a common web interface used by many hosting companies to provide control of the hosting account to manage domains, databases, email,and other hosting account settings and configurations, including software installations.
Not everyone uses this term the same way. When we use it, we mean we manage your WordPress installation, applying software updates and troubleshooting upgrades or other issues as needed, including for most plugins and themes.
MariaDB is a relational database that is a drop-in replacement for MySQL, from which it was forked in 2009.
WordPress is an open-source website content management system (CMS) founded May 27, 2003 by Matt Mullenweg and Mike Little. WordPress was forked from b2 CafeLog, written by Michel Valdrighi in 2001. WordPress is written in PHP and uses (typically) a MySQL or MariaDB database.