Yes. I believe Olson had coined the term in the 50s with his original papers. The one I linked sheds a bit more detail. It's short for 1st order gradient. Multipoles like cardioids, hyper-cardioids, dipoles, etc. Ways of creating directional control, including bass. Its an old concept. Just extremely rare in "high end" home fashion jewelry/audio industry.
I'm sure you're seeing more of it in the pro world
http://www.aes-media.org/sections/pnw/pnwrecaps/2014/subs_june2014/
I hate to say this, AJ, but you have totally lost me in this thread and others, not just with the post I quoted. That, plus, I am getting totally burned out on the photo in post after post. It is annoying, partly because of the simple repetiveness, repetiveness, ... of your posts. You seem to have wanted to win the "frequent poster" championship, which is actually nothing at all to be esteemed or admired. To the contrary, it merely shows that you have failed to communicate and to convince most others of your point of view or of your expertise. So, you redouble your efforts, your arguments and your posts, but to no avail.
I hate to take sides here, but I can logically follow Amir and others in their technical arguments because they make a serious effort to actually communicate. On other hand, you seem to be name, concept and link dropping without a coherent sense of whether or not it is meaningful and comes across. So, you appear to be arguing for argument's sake or to "win" for your often esoteric point of view, to the extent it is comprehensible. But, you are not winning.
You have raised the occasional issue or question worth taking note of amid all the other trivia, or so it comes across. But, if you have a product to sell, if this is part of a marketing push, I fail to be impressed. To the contrary.