- Acronym
- Acrophobia
- Acrostic
- Acrylic
- Act
- Act a lie
- Act of god
- Acuity
- Acute
- Acute angle
- Acutely
- Ad hominem
- Ad rem
- Ada
- Adage
- Adam
- Adamant
- Adaptable
- Adapted
- Add
- Adequately
- Adhered
- Adherence
- Adhesive tape
- Adjectivally
- Adjudicate
- Adjuration
- Adjust
- Adorn
- Adrenal
- Adrift
- Adsorption
- Adulate
- Adulation
- Adult
- Adulterate
- Adulterated
- Adulteration
- Advanced
- Advantage
- Aerial navigation
- Aerial torpedo
- Aerial vehicle
- Aero logy
- Aeromancy
- Aeronautic
- Aerosol
- Aesthetically
- Aestivation
- Afebrile
- Affairs
- Affectedly
- Aficionado
- Afield
- Afloat
- Afore
- Aforethought
- Afraid
- Afro
- After all
- After growth
- After image
- After ones own heart
- After thinking
- After-taste
- Aftershave
- Aggressor
- Aggro
- Aghast
- Agile
- Agistment
- Agitate
- Agitprop
- Agnail
- Agnus castus
- Agonisingly
- Agony aunt
- Agony column
- Agrarian
- Agrarianism
- Agreeableness
- Air conditioner
- Air strike
- Air-conditioned
- Air-mechanic
- Air-pocket
- Air-pump
- Air-raid
- Airborne
- Aircraft
- Aircrew
- Airing cupboard
- Airline
- Airlock
- Airman
- Airport
- Airship
- Airstrip
- Airtight
- Aisle