Parsec

From Slackerpedia Galactica

An attempt to replace one geocentric measuring unit of cosmic length with another geocentric measure. Whereas the Light-year is defined as the distance a photon travels in one Terran year, the parsec is the distance at which an object would have a parallax of one second of arc.

The parsec is about 3.26 light-years, or about 206,265 astronomical units in length, and is equally useless to anyone who is not from Earth.

Don't be fooled by Han Solo's Episode IV reference. A parsec is a unit of distance, not speed. The clue is that Obi Wan rolled his eyes.