Image from Apple.com
If Facebook can trademark Face there is no reason Apple can't trademark Retina for their Retina display, right? Well, whatever your thoughts are on that, Apple has filed a trademark application for Retina.
Much like the Face trademark by Facebook, it's not as big of a deal as many seem to think it is. The Face trademark only applies to anything related to social networking, etc. In other words, anyone in the same business as Facebook. The same thing goes for Retina, Apple's trademark application is for:
Electronic hand-held game units other than those adapted for use with an external display screen or monitor; hand-held electronic games and apparatus other than those adapted for use with television receiver only
So yeah, it only applies to those iDevices everyone is talking about these days.