administrative assistant
• advertising agency
• Advertising Association
• age allowance (for taxation)
• Air Attaché
• Alcoholics Anonymous
• British fishing port registration for Alloa
• Chem. allyl alcohol
• airline flight code for American Airlines
• American Aviation (aircraft)
• Biochem. amino acid
• Chem. andesine anorthosite
• Anglers' Association
• anti-aircraft
• Physics antiproton accumulator
• Biochem. arachidonic acid
• Architectural Association
• Chem. aristolochic acid
• Army Act
• Biochem. ascorbic acid
• Associate in Accounting
• Associate in Agriculture
• Associate in (or of) Arts
• Association of Agriculture
• Astronautica Acta (journal of the International Astronautical Federation)
• Physics atomic absorption
• Physics atomic adsorption
• Augustinians of the Assumption
• author's alteration
• Automobile Association
• Chem. azelaic acid
• British vehicle registration for Bournemouth
• indicating a certificate issued for a ship stating that all crew matters are in order
• (formerly) indicating a film not be shown to a child under 14 unless accompanied by an adult
• Electricity , indicating a size of battery or cell
• Angling , indicating a size of fine split weights