IBM PC
The original IBM PC 5150 released in 1981 and created a pseudo standard that would be copied by other manufacturers. Early on this was coyly advertised by software stating it was "IBM Compatible. Later it would be known as "x86". Due to IBM PC clones quickly dominating the market there isn't any official kind of standard that could be settled on to describe software of this kind. The robust backwards compatibility of CPUs makes it possible to run much older software on new hardware as well.