What does addl stand for?

Additional (GROV)

Additional (KSC)

Aircraft Dummy Deck Landing - Navy

American Double Dutch League (EA)

Amyloid beta Derived Dementing Ligands

Amyloid beta Derived Diffusible Ligands

Animal Disease Diagnostic Lab (FLAA)

Anti-Digit Dialing League (EA)

Association of Drug Detection Laboratories - Medicine (EDAA)