Samsung Foundry unveiled aggressive roadmap scaling down to 4nm
semiengineering.com
semiengineering.com
The +/- on specified dimension, the minimum width of a feature, or....what?
You can see more on the breakdown on pages like this: https://en.wikipedia.org/wiki/10_nanometer
It's more a marketing term since no particular component is exactly 10nm, but it's based on a composite of the features involved.