- Achromatic
- Achyranthus aspera
- Acia
- Airsick
- Acidify
- Acme
- Aconite
- Acquaintance
- Actualist
- Acquaintanceship
- Acquiesce
- Acquisitive
- Acquittal
- Acre
- Acrimonious
- Acrobatic
- Acrobatics
- Acropolis
- Across
- Act of grace
- Actuarial
- Actuary
- Actuate
- Acuate
- Acupuncture
- Ad hoc
- Ad infinitum
- Adamantine
- Adapt
- Adapter
- Add fuel to the fire
- Add insult to injury
- Add operator
- Addict
- Addition
- Additive month
- Address bus
- Address oneself to
- Addressing
- Admirable
- Admiral
- Admiration
- Admirer
- Admiringly
- Admit of
- Adolescent
- Adoption
- Aerobics
- Aerodrome
- Aerogram
- Aeronomy
- Aesthete
- Aesthetical
- Aetiology
- Affability
- Affably
- Affaiars
- Affair
- Affaire de coeur
- Affect
- Affected
- Affectedness
- Afoot
- Aforementioned
- Afraid of his own shadow
- Afrikaans
- After
- After a fashion
- After petticoat
- After that
- Afterbirth
- Afterglow
- Aftermath
- Aggrieve
- Aggrieved
- Agiary
- Agility
- Aglets
- Agnate
- Ago
- Agonizing
- Air hostess
- Air letter
- Airbase
- Airfield
- Airing
- Albatross
- Albumen
- albumin
- Alcoholic
- Alder
- Alehouse
- Alfresco
- Algae
- Alias
- Alice
- Alight
- Aligned
- All over with
- All the