Please see the Domain Name Guide for terminology definitions.
We highly recommend that you use a custom sub-domain name within the department that is most closely associated with your website and/or your employment at Georgia Tech. It is usually quicker and easier to obtain this kind of domain name, which looks like subunit.something.gatech.edu, where "subunit" is most any name except "www" (which is reserved as an alias for the unit's top-level domain).
If your website is for a major unit of Georgia Tech or a very high-level project or activity/event, then you can request a custom top-level domain name, but these requests have to be approved by Institute Communications, and this approval process may take a while. So, you should consider using a sub-domain name (see the previous section) if one could work well enough for your website.