- actinomycosis
- actinon
- actinotherapy
- active anaphylaxis
- active exercise
- active hyperemia
- active immunity
- active movement
- active principle
- active sensitization
- active spectrum
- actomyosin
- acuity
- acupressure
- acupuncture
- acute
- acute abscess
- acute delirium
- acute enteritis
- acute lymphagitis
- acute osteomyelitis
- acute pharyngitis
- acute rheumatism
- acute salpingitis
- acutenaculum
- acyanoblepsia
- acyclic compound
- acystanervia
- acystia
- ad nauseam
- aciduria
- acini hepatis
- acinose
- acladiotic
- aclinic
- acme
- acne
- acne rosacea
- acne seborrhelca
- acnemia
- aconite
- aconitum
- acoumetry
- acoustic
- acoustic agraphia
- acoustic holography
- acoustic image
- acoustic nerve
- acoustic radiation
- acoustic tetanus
- acoustic tubercle
- acoustical reactance
- acquired defect
- acranius
- acrasia
- acro-arthritis
- acro-edema
- acroblast
- acrobrachycephaly
- acrocentric
- acrochordon
- acrocyanosis
- acrodematitis hiemalis
- acrodermatosis
- acrodont
- acrogeria
- acrognosis
- acrokeratosis
- acromelic
- acromial
- acromion
- acromion process
- acronarcotic
- acronyx
- acropachy
- acropetal
- acrosome
- acroteric morphea
- actin
- actinic ray
- actinobacillus
- actinogenic
- actinolite
- actinomycin
- actinophytosis
- action current
- action potential
- aculeate
- acumulative action
- acupuncture needle
- acute abdoman
- acute abdomen
- acute anemia
- acute bronchitis
- acute ear
- acute gastritic
- acute hydrocephalus
- acute myelitis
- acute nephrosis
- acute pile