Drupal and Word Press Google Analytics

Hey, Got one question.

Our main page is using Joomla and the address is Encyclopedia

But our blog, World Book Blogis using Word Press.

When you add a Google Analytics account, it will ask you is is a single domain or not. So is https://www.worldbook.com and blog.worldbook.com a domain with different sub domains?

Sorry I know this question may be silly. But I am not an IT person. So just want to figure it out how to install GA code to our blog.

Thanks!!