What does GMT stand for?

Greenwich Mean Time (GMT) is a time reference that is based on the mean solar time at the Prime Meridian, which runs through Greenwich, London. It was established as the standard for coordinating time across the globe and is used to eliminate confusion about time zones. GMT serves not only as a historical time reference but continues to guide aviation and maritime operations, ensuring that all locations can synchronize schedules despite differing local times.

The term reflects its origin and significance, as GMT represents the time at the Prime Meridian (0 degrees longitude), from which other time zones are calculated either as hours ahead or behind. This makes it particularly essential in international contexts, like aviation, where coordination across various time zones is crucial for safety and scheduling.

The other options do not represent formally recognized or commonly used time standards. For example, General Mean Time, Global Measurement Time, and Geographical Meridian Time are not established concepts within the context of timekeeping or aviation. Thus, their definitions do not align with the widely accepted meaning and use of GMT.