Coordinated Universal Time
Coordinated Universal Time (UTC) is the primary time standard by which the world regulates clocks and time. It is within about 1 second of mean solar time at 0° longitude and does not observe daylight saving time.
UTC and GMT (Greenwich Mean Time) are often used interchangeably, but there's a subtle difference: GMT is a time zone, while UTC is a time standard. For most practical purposes, they show the same time.
UTC (Coordinated Universal Time) is not technically a time zone, but rather the time standard that time zones are based on. It has a UTC offset of +0:00 (UTC+0).
No, UTC does not observe daylight saving time (DST). It remains constant throughout the year, which is why it's used as a reference for global timekeeping.
A Unix timestamp (or Epoch time) is the number of seconds that have elapsed since January 1, 1970 at 00:00:00 UTC. It's widely used in programming to represent dates and times.