About thirty years ago, the 8086 processor was extremely innovative and important. But this processor is, of course, completely obsolete today. However, it continues to have some impact because the instruction architecture that was based on the 8086 is still present in most computers today.
The 8086 was a 16-bit microprocessor that was first produced in 1978 by Intel. The first IBM PCs all used a chip (the 8088) that was a version of the 8086.
So, in layman's terms, this was the microprocessor that made the current structure of computer programming possible. If you are looking for explanations that are not in layman's terms, follow the links.