1.a term used when a person is refering to something technical about which he has no real knowlege.
2.often used in a response to the question "What were you doing?"
Originally used in the movie "Tommy Boy" with Chris Farley.
1.Q:"Hey, do you know what's wrong with my computer?"
A:Yeah just a second I think there may be a problem with the rotary girder.
2.Q:"Dude, what the hell are you doing?"
A: Sorry, I was just checking the specs on the rotary girder.