GPS is a system that tells you where you are on Earth. Satellites send out radio signals; a phone, a car box, or a watch listens to several of them at once and works out your place, often to a few metres. The letters stand for Global Positioning System — first built as a US military tool, now inside ordinary maps, taxis, hiking watches, and “share my location.” People say GPS both for the satellite system and for the little device or the pin on the screen. Though actually, your phone map is not only GPS: it also uses phone towers, Wi-Fi, and sometimes other countries’ satellites, but most people still call the whole locating thing GPS. The satellites themselves do not need your mobile data; the map pictures on the screen usually do. The word is neutral and everyday, as ordinary as “Wi-Fi.” People also stretch it: “What’s the GPS?” meaning “What’s the location?” which is loose but widely understood.