Wow, that was a good one. I immediately thought, "Oh, that's easy, it's... wait a sec... I don't know!!"
Anyway, I googled and found a fairly obscure reference to the Institute of Radio Engineers! Apparently (I didn't know this, either), according to a Tektronix page I found, the IRE later became the IEEE!
Mystery solved. Here's a page with more information than you ever wanted to know about IEEE/IRE...
A forum community dedicated to home theater owners and enthusiasts. Come join the discussion about home audio/video, TVs, projectors, screens, receivers, speakers, projects, DIY’s, product reviews, accessories, classifieds, and more!