- Advocacy
- Adze
- Aegis
- Aeon
- Aeration
- Affectionately
- Affinity with (for, between)
- Affix
- Affluenza
- Affright
- Affront
- Affronted by
- Afterthought
- Again
- Against the grain
- Against the hair
- Agamas
- Agate
- Age
- Age of shams
- Aged bull
- Ageism
- Agency
- Agent
- Ages
- Agglutinate
- Airsickness
- Agreed
- Agriculturist
- Agro
- Agroforestry
- Ahalya
- Ahead of
- Ahem
- Ai
- Aid
- Aide
- Aids
- Aileron
- Ailment
- Aimed
- Aimlessly
- Aimlessness
- Alas
- Alas!
- Albion
- Alcoholism
- Alcove
- Ale
- Alexander
- Alga
- Algonquin
- All over
- All person
- All right
- All star
- All such
- All the way
- All time
- All-pervading
- All-purpose
- All-wise
- Allayment
- Amatory
- Allergic
- Allergic to
- Alley
- Alleyway
- Allied
- Alligator
- Alliteration
- Allopathic
- Allot
- Allow in
- Allowable
- Allowed
- Alloy
- Allure
- Alluring
- Allusion
- Altered
- Alternately
- Alternating current
- Alternation
- Alternator
- Altitude
- Altruism
- Altruistic
- Alu
- Alumna
- Alumnus
- Alzheimer's disease
- Amalgamation
- Amassed
- Amative
- Amethyst
- Amicably
- Amicue curie
- Amidst
- Amoeba