I just bought hosting for my domain; it comes with cPanel.

The cPanel tutorials on youtube sometimes mention Wordpress. I suspect I don't need Wordpress but am curious for a brief description of it. I searched for a brief summary description but did not find one.

It a blog software. If you aren't going to run a blog you don't need it. If you are, you may want to go through the options befrore you decide what program to use. WordPress isn't the only blog software out there, but probably the most used one. You don't have to use it just because it's integrated with your CP.