UTC, short for Coordinated Universal Time, is a standard time reference used globally. However, there can be instances where one may need to use a synonym for this term. Some alternatives may include Zulu Time, Greenwich Mean Time (GMT), or World Time. Zulu Time is primarily used in aviation and maritime industries and is the same as UTC, while GMT is the time standard at the Royal Observatory in Greenwich, London. World Time refers to the various time zones across the globe. It's worth noting that while these terms may be used interchangeably, UTC is the most widely recognized standard.