- akimbo
- augustan
- alexandrite
- aegle marmelos
- amoebic
- augean stables
- adiabatic
- arithmetician
- asymmetric
- armenia
- asynchronous
- against the clock
- ascending node
- aliquot part
- aerolite
- alsatia
- adviser
- accretion
- animosity
- at any price
- auroral
- arrester
- aphelion
- auricular
- auriculated
- at a push
- antarctic continent
- antarctic ocean
- abraded
- Au fond
- Appetent
- Arisen
- Approver
- About-turn
- Ammeter
- About-face
- Autonomic
- Agents
- Abased
- Abbreviating
- Abolished
- Aborted
- Above-mentioned
- Above-named
- Anthropocentric
- Anteriorly
- Anti-aircraft
- Antidotal
- Antimatter
- Absent-mindedness