# What's the difference between semiconductor and insulator (besides band gap)?

The typical classification of electronic materials is metal-semiconductor-insulator. Is there any actual difference between a semiconductor and an insulator, besides the size of the bandgap?

Basically they are the same from a physics point of view, if you only look at crystalline materials. A semiconductor is defined to be insulating at $0 K$, while conducting at room temperature, although I don't recall, what level of conductivity is required to count as semiconductor.