from http://www.trs-80.org/multiplan/

    "Originally code-named “EP” (for “Electronic Paper”), Multiplan was written to use a very clever p-code compiler system created by Richard Brodie. This p-code system, which was also used later by Microsoft Word, allowed Microsoft to target Multiplan to a huge number of different 8-bit and 16-bit computer systems. (Charles Simonyi once estimated that Multiplan was available for 100 platforms.)"

Many people say that the 'p' in 'p-code' stands for 'pseudo', i.e. pseudo code. But the article archived at https://techshelps.github.io/MSDN/BACKGRND/html/msdn_c7pcode... says the 'p' is short for 'packed'.

    "Microsoft has introduced a code compression technology in its C/C++ Development System for Windows version 7.0 (C/C++ 7.0) called p-code (short for packed code) that provides programmers with a flexible and easy-to-implement solution for minimizing an application's memory requirements. In most cases, p-code can reduce the size of an executable file by about 40 percent. For example, the Windows Project Manager version 1.0 (resource files not included) shrinks from 932K (C/C ++ 7.0 with size optimizations turned on) to 556K when p-code is employed."

    "Until now, p-code has been a proprietary technology developed by the applications group at Microsoft and used on a variety of internal projects. The retail releases of Microsoft Excel, Word, PowerPoint�, and other applications employ this technology to provide extensive breadth of functionality without consuming inordinate amounts of memory."