- Alopecia
- Alpine
- Alright
- Alsatian
- Also
- Alstonia genus
- Altair
- Altar
- Alter
- Alternative
- Alternative energy
- Alternatively
- Alto
- Alum
- Always
- Am
- Amalgamate
- Amateur
- American football
- American indian
- Americanism
- Americium
- Amerindian
- Amiability
- Amiableness
- Amicus curiae
- Amid
- Ammunition
- Amniocentesis
- Among
- Amorality
- Amorous
- Amortize
- Amperage
- Ampere
- Amplifier
- Amplify
- Amply
- Ampoule
- Amputate
- Amuck
- Amusement
- Anabolism
- Anacardium occidentale
- Anaemia
- Anaesthetist
- Analogous
- Analogy
- Analysable
- Analyse, analyze
- Anandavardhana
- Anarchism
- Anarchist
- Anasarca
- Anecdote
- Anemia
- Anencephalus
- Anent
- Anesthetic
- Anesthetist
- Aneurysms
- Anger
- Angina
- Angiras
- Anglicize
- Angling
- Anglo
- Anglophone
- Angora
- Angry
- Annihilated
- Annihilation
- Annualized
- Annuity
- Annus mirabilis
- Anodise
- Anomalous
- Anonym
- Anus
- Anonymous letter
- Anorexic
- Another key
- Answer back to
- Answer for
- Antechamber
- Antennae
- Antepenultimate
- Anticipation
- Anticipative
- Antihelmintic
- Antihistamines
- Antilog
- Antilogarithm
- Antimacassar
- Antinomy
- Antiquity
- Antithesis
- Antithetical
- Antitype
- Antral gastritis