In real life, our calendar and years are denoted as “B.C.” and “A.D.,” which is heavily influenced by Christianity. As noted by, B.C. stands for “before Christ,” while A.D. is Latin for “anno domini,” which translates to “in the year of the lord.” So, what does “BBY” mean in “Star Wars?” Does it mean “before Baby Yoda,” for example?
Unfortunately, no, Grogu is not part of the Star Wars dating system. However, BBY does stand for an incredibly historical moment in the “Star Wars” universe, which is the Battle of Yavin.
For the non-hardcore “Star Wars” fans, Yavin is the planet that hosts the secretive base of the Rebel Alliance in the first “Star Wars” movie. The Battle of Yavin actually refers to the skirmish that results in the destruction of the first Death Star. This means that “Andor” takes place five years before this momentous event — a victory that Cassian Andor is partially responsible for, on account of him aiding in the stealing of the original Death Star plans during the events of “Rogue One.” By stealing the plans, Andor and the rest of his team provide the Rebel Alliance with the means in which to destroy the Death Star, which would have become yet another symbol of Imperial oppression. From that point on, the years are denoted as “Before the Battle of Yavin,” aka BBY, or “After the Battle of Yavin,” or “ABY.”
Although Cassian himself will never refer to the year with that qualifier, it helps viewers place these events in the grand scope of the “Star Wars” story.