What does the "nm" figure in a modern chip process node actually represent?

The "nm" figure in a chip's process node name today functions mainly as a marketing label rather than a literal measurement of any transistor feature, since actual transistor dimensions stopped tracking those numbers as manufacturing techniques evolved well past what a simple linear shrink could describe.

It is not the exact width of a transistor's gate; gate lengths on modern chips are often larger than the node name would suggest, since density and performance now come from three-dimensional structures rather than pure shrinkage. It also isn't the spacing between memory cells, which is a separate measurement entirely.

This naming drift means comparing a "3nm" chip from one company to a "3nm" chip from a rival isn't a straightforward apples-to-apples comparison, since each manufacturer defines its own node names, making real performance benchmarks far more informative than the label alone.