Taking a term out of context and then sticking it next to another term doesn't make it clear. It makes it confusing. Think about terms like "irradiated food" (failed in the market) or "nuclear magnetic resonance imaging" (had to drop the N-word) which ran into exactly this problem.

You probably have some idea about how GPUs work, so the idea of having "multi core" ones wasn't shocking to you. Most of the people to whom that presentation was targetted don't have that context. To them, it sounds like "The Quad-Core A5X CPU enables faster graphics!", which is perfectly reasonable IMHO, and matches the use of Quad-Core in other contexts they know.

But Apple, of all companies, knows this already. They are masters of communication strategy. They picked "Quad-Core" deliberately, probably as an attempt to dilute the branding Tegra has already established with it. And that's sleazy.

It's not out of context. PowerVR advertises the SGXMP series as a multi-core solution: http://www.imgtec.com/News/Release/index.asp?NewsID=449

"The technology, henceforth POWERVR SGX543MP, is being delivered to customers in SGXMP2 (two-core) to SGXMP16 (16-core) variants."

I like to think of myself as more technologically aware than an average consumer, and I've never heard of PowerVR. The manufacturers of graphics hardware I do know never use cores in their marketing.