PMP here means portable media player: a small machine you carry with you to play music, videos, or other files, without a computer. Think of the old iPod and other MP3 players — that family of gadgets. The name was common in the 2000s, when these little players were new and people bought them as their own thing. Today most people just use a phone, so you will meet PMP more in older manuals, shop lists, and tech writing than in everyday talk. It is a dry, technical short name, not a warm spoken word. The same three letters also stand for other things (including a project-management qualification), so this meaning is only the music-and-video player.