abstraction; acceptor number (AN); acid; acidity; acidity function; activated complex; activation energy; addend; addition; addition reaction; additivity principle; adduct; A-factor; agostic; alcoholysis; allylic substitution reaction; alternant; ambident; amphiphilic; amphiprotic (solvent); amphoteric; anchimeric assistance; anionotropic rearrangement (or anionotropy); anion radical; annelation; annulation; annulene; antarafacial, suprafacial; anti; antiaromatic; anti-Hammond effect; anti-Markownikoff addition; aprotic (solvent); aquation; aromatic,aromaticity; Arrhenius equation; aryne; association;asymmetricinduction; atomic orbital;ttachment;autocatalytic reaction; automerization; autoprotolysis; autoprotolysis constant....