There are four possible combinations of blood types namely: Type A (only antigen A), Type B (only antigen B), Type AB (both antigens A and B), and Type O (neither antigens A nor B). This is referred to as the ABO blood typing system. In addition, red blood cells have a Rhesus factor or Rh, which is either present or absent. If the Rh factor is present, the cells are referred to as Rh positive.
Looking for the definition of DFAC? Find out what is the full meaning of DFAC on Abbreviations.com! 'Dining Facilities Administration Center' is one option -- get in to view more @ The Web's largest and most authoritative acronyms and abbreviations resource.
In the Army, and I seem to remember it being in the Air Force too, TAC stands for Training, Advising, and Counseling, which would makes a lot more sense considering what TACs do. As I've researched this online, it seems that in CAP, using the term Tactical Officer instead of Training, Advising, and Counseling Officer is somewhat widespread.