- a kind of flute
- a pure consonant
- an intelligence man
- a large spider
- a throb
- absentmindedly
- anisogamy
- amphinaphthaquinone
- aphorist
- anomalist
- adscripted
- adsl
- a measure of weight equivalent to five seers
- antihaemorrhagic
- an etymologist
- absolute reaction rate
- apothecaries' pound
- after_birth
- agaricic acid
- auriculate
- antiliming
- antineutrino
- atelectasis
- atrial septal defect
- Alstroemeria pelegrina
- aganglionosis
- amphineura
- amphioxus
- apneic
- amphistomatic
- aspherical
- akerlund deformity
- audenesque
- adiabtic condition
- allhallowtide
- aloe emodin
- alismatidae
- absolute system of units
- argument list
- astronomical year
- a man of many parts
- as good as the next man
- alphanumeric edited character
- anionic detergent
- anionic
- arame
- acquired reflex
- analgesiometer
- antidiphtheritic serum
- amitriptyline