A term from the sci-fi series Stargate SG-1, which basically means "people of Earth." (Pronounced TAH-ree.)
Yeah, I know what you're saying: "But, I thought we were called 'Earthlings' or 'Terrans' or something like that!?" Indeed. To understand, you'll need a little bit of background about SG-1.
The original Stargate movie and the SG-1 television series created a science fiction universe in which there are thousands of humanoid-inhabited planets throughout the galaxy. But originally, humans were found on only one planet: Earth. Sometime in Earth's past, presumably during the time of the Ancient Egyptians, an alien race known as the Goa'uld invaded Earth, enslaved everybody, and started farming folks out to other planets via the Chaapa'ai (aka Stargate), a piece of alien technology co-opted by the Goa'ulds for their own nefarious transportation needs.
Fast forward to present day. Having overthrown their Goa'uld oppressors millennia ago, the people of Earth know next to nothing about the ancient "gods" who ruled the planet, and nobody's ever even heard of the Chaapa'ai. Meanwhile, humans living on other planets across the galaxy have gone so long without hearing from Earth, they've pretty much dismissed the Tauri as a legend or myth.
Thus, you have a group of people (us) who are known throughout the universe by one name ("the people of the Tauri," or simply, "the Tauri") and known to themselves as something different ("Earthlings," "Terrans," "Americans," "hardcore porn addicts," etc.). The rest, as they say, is history...well, fictional history...anyway, you get the point.