Galactic Standard refers to the accepted measurement of time by all the sentient species in the galaxy. The galactic standard year, abbreviated "gs", begins as the year 1gs, in which the Druogs invented a means of interstellar travel. However, it wasn't until roughly 200 years later that the galactic standard system was adopted. The galactic standard year is how events are organized in Timeline 60-77.
The Galactic Year is 366 Galactic Days. This is the average amount of time it takes for the planets in the Daeron System to orbit their sun. A Galactic Day is 23.8 hours long, which is very similar to an Earth Day. This day length is the average amount of time it takes for planets in the Daeron System to rotate on their axis. The Galactic Year also is similar to an Earth year, with only one extra day
Conflicts with Human Time
At first it was difficult for Humans to adapt to the Galactic timeline. The events of the first Galactic Standard year occurred in roughly 560BCE (Before common era) on the Human Gregorian Calendar. Humans have to, essentially, subtract 560 years from the current Galactic Standard year to find the AD (anno domini) year on the Human calendar.