What exactly does nm measure?

[alexsabree]

Recently ive been hearing how some cpus are moving to 45nm and ive been wondering what exactly nm means? I think it means NanoMeter, but i have no idea what its measuring.

So what is a nm?

Thanks in advance,
alexsabree

 

[rx7i2]

It's the die size of the core. The smaller it is, the less power it consumes

 

[aspire]

nm = nano meter

 

[veg1992]

nanometer, smaller it is better, less power consumption, emits less heat, temps are lower

 

[alexsabree]

so the die size is the actual size of the chip in diameter?

Edit) I know that lower nm on a processor = better but im trying to understand why, and what exactly its measuring.