Orbis in itself does not mean too much, standing for "circle" or "ring" in Latin. The site speculates, however, that it could be called Orbis Vita, which in turn means "the circle of life." The PS Vita, Sony's newly released handheld, could have a large part in the next-generation console if this is true.
Adding to confirmation of "Orbis" is the active developer portal. Just like vita.scedevnet.com is the portal for Vita devs, orbis.scedev.net leads to a working address.
Some bad news on the front of gaming is that the Orbis will not be backwards compatible with PS3 games, nor will it allow used games. The console (and your PSN account) will lock out games already attached to other people's consoles. This rumor is start to steam roll, after sites speculated Microsoft was working on a similar scheme.
The specs were very, very vague, but developers are being told to work on a AMD x64 CPU and a AMD Southern Islands GPU. Says Kotaku: "The PS4's GPU in particular, we're told, will be capable of displaying Orbis games at a resolution of up to 4096x2160, which is far in excess of the needs of most current HDTV sets. It'll also be capable of playing 3D games in 1080p (the PS3 could only safely manage 3D at 720p)."
If accurate, the PS Orbis Vita will be released in time for the holidays of 2013.