Medical terminology is composed of a prefix, root word, and suffix. It is used to precisely describe the human body components, processes, illnesses, medical procedures, and pharmacology. Medical terminology is used in the field of medicine, and clinical settings. This section deals with all med terms beginning with a letter A.

a-   no; not; without
an-     no; not; without
ab-      away from
abdomin/o      abdomen
-ac      pertaining to
acanth/o       spiny; thorny
acar/o       mites
acetabul/o   acetabulum (hip socket)
acous/o       hearing
acoust/o       hearing, sound
acr/o        extremities; top; extreme point
acromi/o         acromion (extension of shoulder bone)
actin/o         light
acu/o      sharp; severe; sudden
-acusis       hearing
ad-       toward
-ad       toward
aden/o       gland
adenoid/o   adenoids
adip/o        fat
adren/o       adrenal gland
adrenal/o   adrenal gland
aer/o       air
af-       toward
agglutin/o   clumping; sticking together
-agogue      producer, leader
-agon       to assemble; gather
agora-       marketplace
-agra       excessive pain
-al       pertaining to
alb/o       white
albin/o       white
albumin/o   albumin (protein)
alges/o       sensitivity to pain
-algesia       sensitivity to pain
-algia       pain
all/o       other
alveol/o        alveolus; air sac; small sac
ambi-       around, on both sides, about
ambly/o       dim; dull
amphi-      around, on both sides
-amine       nitrogen compound
ammon/o        ammonium
amni/o      amnion (sac surrounding the embryo)
amyl/o       starch
an/o      anus
-an       pertaining to
ana-    up; apart; backward; again; anew
andr/o       male
aneurysm/o   aneurysm (widening of blood vessel)
angi/o       vessel (blood)
anis/o       unequal
ankyl/o       stiff
ante-       before; forward
anter/o       front
anthrac/o   coal
anthr/o       antrum of the stomach
anti-       against
anxi/o       uneasy; anxious
aort/o       aorta (largest artery)
-apheresis    removal
aphth/o        ulcer
apo-       off; away
aponeur/o   aponeurosis (type of tendon)
append/o       appendix
appendic/o   appendix
aque/o       water
-ar       pertaining to
arachn/o       spider
-arche       beginning
arsenic/o    arsenic
arter/o       artery
arteri/o       artery
arteriol/o   arteriole (small artery)
arthr/o      joint
-arthria       articulate (speak distinctly)
articul/o   joint
-artresia   closure, occlusion
atreto-       closed, lacking an opening
-ary       pertaining to
asbest/o       asbestos
-ase       enzyme
aspir/o      removal
-assay      to examine, analyze
-asthenia   lack of strength
astr/o       star, star-shaped
aque/o      water
atel/o       incomplete
ather/o      plaque (fatty substance)
-ation      process; condition
atri/o      atrium (upper heart chamber)
atmo-       steam, vapor
audi/o       hearing
audit/o       hearing
aur/o       ear
auricul/o   ear
auscult/o   to listen
aut/o       self; own
aut-       self; own
auto-       self; own
aux/o       growth, acceleration
axill/o       armpit
axi/o       axis
azot/o       urea; nitrogen


Check out the following resources to support your learning and understanding of medical terminology:

  • Quick Introduction– provides an overview and introduction to medical terminology.
  • Word Building Reference– This resource strengthens your understanding of medical terminology. See how common medical terms are created using the various prefixes, suffixes, and root words.
  • Medical Terms – rules governing singular versus plural versions of medical terms are described.
  • Medical Terminology Exams– twenty new exams were created to test your knowledge of medical terminology.