A family of instruction set architectures originally based on the Intel 8086 CPU that functions with a very wide array of operating systems, including Windows, MacOS X, Linux, BSD, and Solaris.
x86 is a family of instruction set architectures. Usually, it refers to binary compatibility with the 32-bit instruction set of the 80386 processor.
Questions on x86 should not just be about a version of an OS that happens to use x86.
x86 denotes a family of instruction set architectures based on the Intel 8086 CPU. The 8086 was introduced in 1978 as a fully 16-bit extension of Intel's 8-bit based 8080 microprocessor and also introduced memory segmentation to overcome the 16-bit addressing barrier of such designs. The term x86 derived from the fact that early successors to the 8086 also had names ending with "86". Many additions and extensions have been added to the x86 instruction set over the years, almost consistently with full backward compatibility. The architecture has been implemented in processors from Intel, Cyrix, Advanced Micro Devices, VIA and many other companies.