3ps means:"third person shooter" this means that the camera is angled to the position where u can see the body of the ingame player character that a player is playing in a shooter game,
the word 3ps is similar like "FPS" which means... "first person shooter" this is where the camera is angled to the view of the player character's eyes, so u can see your hands/arms/ "in newer games"stomach/and leg and feet", just like when u see your body through your eyes, unlike 3ps where u see the the most part of the ingame player's body character a player is playing,
GUY1: what do u prefer? 3ps or fps?
GUY2: i prefer FPS because i get a more clear view infront of me,
GUY1: oh really?
GUY2: yeah its also more realistic and immersive
GUY1: i prefer 3ps because you can see all of the action,