The web address you choose for your site can be an integral part of how you communicate to your audience and market your program or center.
An abbreviation or acronym is fine if you're an administrative unit on campus (e.g. University Personnel, sjsu.edu/up). Otherwise, try and choose something that is descriptive, but easy to remember.
Multiple words are okay, but not ideal, as printed materiel or online videos recommending people visit sjsu.edu/applied-occlumenical-theory aren't quite as easy to type or remember as sjsu.edu/occlumency.