BBY/ABY is used to position items along the Star Wars Timeline. BBY refers to Before the Battle of Yavin. ABY refers to After the Battle of Yavin. The Battle of Yavin in Episode IV: A New Hope occured in 0 BBY/ABY.
Caleb Dume's first days in The Clone Wars continue…Master Billaba brings her Padawan and their clones to the Battle of Mygeeto. Separatist Generals Sear and Grievous lay in wait…