Modding is changing something — most often a computer game or other software — so it works in a new way the makers did not ship. People add new maps, new clothes for characters, extra tools, or they fix something they do not like. The changed piece is a mod; modding is the doing. The word is informal and lives with fans and hobby people, especially gamers. You also hear it for changing a computer case or a car, but the centre of the word today is software. Though actually, not every change is modding. Updating an app the normal way is not. Building a program from nothing is not. Modding starts from something that already exists and reshapes it, usually on your own machine. This mod is short for modification / modify. It is not the “mod” who watches a chat room (that is moderator), and not the 1960s British Mods with scooters and sharp suits — same letters, different stories.