How to execute WordPress as though it is in the root folder while it is installed in a subdirectory?

WordPress has a good writeup about this at Giving_WordPress_Its_Own_Directory.

Many people want WordPress to power their site’s root (e.g. http://example.com) but they don’t want all of the WordPress files cluttering up their root directory. WordPress allows you to install it into a subdirectory, but have your blog exist in the site root.

You could also just redirect from the root directory to /wordpress but keep the URL aliased as mydomain.tld.