The nine stars symbolize the archipelago’s nine islands.
The name of the archipelago comes from the Portuguese word açor, meaning goshawk, because it was supposed to be a common bird at the time of the discovery. However these birds never existed on the islands, they actually were a local subspecies of the buzzard (Buteo buteo), that was erroneously identified as goshawks by the first explorers.
The shield of Portugal present in the top left corner of the flag represents the Portuguese patriotism of the Azorean people.