IBM PC is a computer released in 1981 by IBM, as well as an entire series of computers compatible with it. It is still the dominant computer platform in desktops, laptops and servers, even though (and maybe because) IBM lost its grip of it by the 1990s. Modern x86 processors remain software-compatible with the Intel 8088 processor of the original IBM PC, even though it is no longer possible to run all the software natively. The operating system of the original IBM PC was Microsoft's DOS (PC-DOS, MS-DOS) which was surpassed in popularity by Microsoft ?Windows in the 1990s.
The ubiquity of IBM PC compatibles as well as the lack of a single corporation that controls the platform makes it a good candidate for a bedrock platform.
The Wintel platform (consisting of IBM PC compatible hardware and a Windows operating system) represented a technological monoculture especially in the early 2000s, when non-x86 computers had been marginalized, ARM-based mobile computers were not yet common, and most applications weren't yet being targeted for web browsers.
Sometimes, "PC" is used as a shorthand for "IBM PC compatible", while sometimes it refers to a "personal computer" in general. This may lead to misunderstandings and misconceptions, such as regarding the original IBM PC more revolutionary than it actually was in the early years.