Physics acoustic plasmon
• Physiol. action potential
• (or A/P) Insurance additional premium
• Grammar adjective phrase
• aerosol particle
• (USA ) airplane
• (USA ) Air Police
• air pollution
• air publication (Ministry of Defence)
• (Spain ) Alianza Popular (Popular Alliance; political party)
• Chem. alkaline permanganate
• Biochem. alkaline phosphatase
• (USA ) American plan (of paying hotel bills)
• Chem. ammonium perchlorate
• Surveying Amsterdamsch Peil (German: Amsterdam level; mean level used in the Netherlands, Belgium, and N Germany)
• Andhra Pradesh
• Med. angina pectoris
• Med. anteroposterior
• Med. anterior pituitary
• antipersonnel
• Commerce à protester (French: to be protested; on bills of exchange)
• armour-piercing
• Computing array processor
• Med. arterial (blood) pressure
• Associated Presbyterian
• Associated Press
• atomic power
• (or A/p) authority to pay (or purchase)
• automotive products
• Insurance average payable
• British vehicle registration for Brighton
• international civil aircraft marking for Pakistan