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Apparently "CCD" stands for "core-complex die", a dumb acronym that just means "chip with cores", and different from the other "chip with i/o interconnect" you also get in a module.

It is annoyingly rare to find anybody expanding this acronym.

A meaningful definition of "CCX" is harder to find.

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CCX or core complex is a lower level grouping of cores. On Zen 2/3 the CCX would have 4 cores on a little ring bus. A full 8-core CCD would then have two of those 4-core CCXs connected via infinity fabric. The inter-CCD connections were also made with infinity fabric between the CCXs.

Zen 4 increases the CCX size to 8, so each CCD only has one.

I can't remember exactly how Zen 1 worked but I think it was different.

Nit: Zen 3 increased the CCX size to 8 cores.

You have the generations there a bit off. Zen 1/2 were 4-core CCXs and it was Zen 3 that switched to 8 core CCXs. Zen 2 is what introduced the CCD, but kept Zen 1's CCX.

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