That's the etching size of the processor. Simply put, that is, we can carve a unit of transistor on a chip of what size. Mobile phone processors are different from ordinary computer processors, and the size that can be left for it in a mobile phone is quite limited. The smaller the etching size, the more computing units there are in the same size processor, and the stronger the performance;
At the same time, advanced etching technology can also reduce the resistance between transistors, so that the voltage required by the CPU is reduced, so that the power required to drive them is also greatly reduced, effectively reducing power consumption and heat. Therefore, the 7-nanometer chip not only means that the size area is smaller, but also the performance of all aspects will be improved between generations