So here’s the story of the confusing (if you looked into it deeper) naming of Intel’s CPUs.
It began with their mobile CPU, a 32-bit next generation of the Pentium M. They probably asked marketing what name would be cool. And the geniuses came up with “Intel Core“.
Then Intel developed a new micro-architecture, which is new, and cool, and 64-bit. What did they decide to name it? “Intel Core”. D’oh! OK, to avoid confusion you should call it “Intel Core Microarchitecture“.
Then they wanted to sell CPUs with this new architecture. So they probably asked marketing again for an appropriate brand for CPUs equipped with it. “How about, ‘Intel Core 2‘?”…
So now you have Intel Core (CPUs), which doesn’t have Core (the micro-arch), and Intel Core 2, which does have Core (the micro-arch). And because two is better than one, they sell Core Duo, which just means 2 cores of Core, and a word “Duo” which means 2 in Latin. Yeehaw! There’s also Core 2 Duo, a chip with 2 cores of Core 2.
Simple, right?