A Short French Lesson

Because I am a dork, I am watching my hero Alton Brown (I almost just wrote Ashton, ack) doing a show about kebabs. I love me som Good Eats, but I have to question his info sources on one thing. While explaining parts of a cow, he got to sirloin and said "something something blah blah blah the 'sir' of sirloin comes from the French, meaning under, which means it is from under the loin." (Obviously an exact quote.) Well, assuming he is referring to the French word 'sur', I am afraid he is gravely mistaken. Any good French fag (like me) will know what sur=on and sous=under. Bad Alton!