1, The full form of GMT is Greenwich Mean Time. It’s used on Regional ,Time Zones in Worldwide

Greenwich Mean Time (GMT) is a term originally referring to mean solar time at the Royal Observatory in Greenwich, London. Greenwich Mean Time (GMT) was established in 1884 at the International Meridian Conference, when it was decided to the place the Prime Meridian at Greenwich, England.

2, The full form of GMT is Generic Mapping Tools. It’s used on Computing ,Sofware & Applications in Worldwide

The Generic Mapping Tools (GMT) are an open-source collection of computer software tools for processing and displaying xy and xyz datasets, including rasterisation, filtering and other image processing operations, and various kinds of map projections.

3, The full form of GMT is Giant Magellan Telescope. It’s used on Academic & Science ,Astronomy & Space Science in Worldwide

The Giant Magellan Telescope (GMT) is a ground-based extremely large telescope planned for completion in 2018. It will consist of seven 8.4 m (27.6 ft) diameter primary segments, with the resolving power of a 24.5 m (80.4 ft) primary mirror and collecting area equivalent to 21.4 m (70.2 ft) one. The telescope is expected to have over four times the light-gathering ability of existing instruments.