The name used to correspond to the minimum gate length down to ~14nm. But the smallest feature size in 3nm (i.e. minimum gate length) is certainly much smaller than 24nm.
I couldn't find the information readily available online so I'm not sure I can answer that (all of this stuff is under NDA). But even then, I could only tell you the "drawn" dimension, which is what gets shown on the screen. There are a lot of digital and physical processing steps that change the actual dimensions. Once something is manufactured inevitably one of the IC teardown companies will do a cross section and publish all of this information.
