[xw390111]

All it means is average transistor density went up. It's supposed to mean by 2x but, in practice, it doesn't even mean that really. i.e. "At the 2020 IEEE IEDM conference, TSMC reported their 5nm process had 1.84x higher density than their 7nm process." [2]

And there are a lot stuff in there besides transistors: contacts, metal traces, power routing, ...

And there's also the quality of the software that draws the transistors. (No one draws billions of transistors by hand) And to further complicate things, there are many good reasons to make your transistors larger than the minimize size, and in fact many are.

So, it vaguely means density went up and unfortunately there isn't a single resource that says how to measure it or what the limit is.

Come to think of it, It's kind of like Moore's Law (the topic of TFA) in that it used to have a definite meaning. But then the meaning sort of evolved over time into something else without society actually agreeing on what that "else" was.

[2] https://fuse.wikichip.org/news/3398/tsmc-details-5-nm/