This document provides definitions for common prefixes used in medical terminology. It lists over 150 prefixes and provides a brief definition for each one, explaining how the prefix relates to or modifies the meaning of the root word it is attached to. Some common themes in the prefixes are parts of the body (abdomin-, cardi-, dermato-), processes or conditions (-itis, -algia, -osis), sizes (macro-, micro-, mega-), and directions or locations (ante-, intra-, retro-). The document serves as a reference for understanding how medical terminology is constructed through the combination of prefixes, roots, and suffixes.

1. A
a-, an- Without; away from; not.
ab-, abs- From; away from; absent.
abdomin-, abdomino- Abdomen.
abort-, aborto- To miscarry.
abs- SEE: ab-.
acanth-, acantho- Thorn; spine.
acous-, acoust-, acousto- Hearing.
acro- Extremity; top; extreme point.
actin-, actino- Ray; some form of radiation.
ad- Adherence; increase; toward.
-ad Toward; in the direction of.
aden-, adeno- Gland.
adip-, adipo- Fat.
adren-, adreno- Adrenal glands.
adrenal-, adrenalo- Adrenal glands.
-aemia Blood.
aer-, aero- Air or gas.
-aesthesia, aesthesio- SEE: -esthesia.
af- Toward.
-agogue An agent that promotes the expulsion of a
specific substance.

2. -agra Sudden severe pain.
-al 1. Relating to, e.g., abdominal, intestinal. 2. In
chemistry, an aldehyde.
albumin-, albumino- Albumin.
-algesia, -algia Suffering; pain.
algi- Pain.
all- SEE: allo-.
allo-, all- Other.
amb-, ambi- Both; on both sides; around; about.
amph-, amphi-, ampho- Both; on both sides; on all
sides; double; around; about.
an- SEE: a-.
ana-, an- Up; against; back.
andro- Man; male; masculine.
angi-, angio- Blood or lymph vessels.
aniso- Unequal; asymmetrical; dissimilar.
ankyl-, ankylo- Crooked; bent; fusion or growing
together of parts.
ante- Before.
antero- Anterior; front; before.
anthropo- Human beings; human life.
ant-, anti- Against.
antr-, antro- Antrum.

3. apo- From; derived from; separated from; opposed.
arch-, arche-, archi- First; principal; beginning; original.
arteri-, arterio- Artery.
arthr-, arthro- Joint.
-ase Enzyme.
-asis, -esis, -iasis, -isis, -sis Condition; pathological
state.
astro- Star; star-shaped.
atelo- Imperfect; incomplete.
ather-, athero- Fatty plaque.
atmo- Steam; vapor.
atreto- Absence of an opening.
aut-, auto- Self.
axio- Axis; the long axis of a tooth.
axo- Axis; axon.
azot-, azoto- Nitrogenous compounds.
B
bacteri-, bacterio- Bacteria; bacterium.
balan-, balano- Glans clitoridis; glans penis.
bar-, baro- Weight; pressure.
basi-, basio- Base; foundation.
bi-, bis- Two; double; twice.
bili- Bile.
bio- Life.
bis- SEE: bi-.

4. blast-, -blast Germ; bud; embryonic state of
development.
blenn-, blenno- Mucus.
blephar-, blepharo- Eyelid.
brachio- Arm.
brachy- Short.
brady- Slow.
brom-, bromo- Bromine.
bronch-, bronchi-, broncho- Airway.
bronchiol-, bronchiolo- Bronchiole.
C
cac-, caci-, caco- Bad; ill.
calc-, calco- Calcium.
calcan-, calcaneo- Calcaneum (heel bone).
carcin-, carcino- Cancer.
cardi-, cardio- Heart.
carpo- Carpus.
cary-, caryo- SEE: kary-.
cat-, cata-, cath-, kat-, kata- Down; downward;
destructive; against; according to.
cath- SEE: cat-.
cel-, celo- 1. Tumor; hernia. 2. Cavity.

5. -cele Tumor; swelling; hernia.
cent- Hundred.
cephal-, cephalo- Head.
cerebell-, cerebello- Cerebellum.
cervic-, cervico- Neck; the neck of an organ.
cheil-, cheilo- SEE: chil-.
chem-, chemo- Chemical; drug.
chil-, chilo- Lip; lips.
chir-, chiro- Hand.
chlor-, chloro- Green.
chol-, chole- Bile; gall.
cholangi-, cholangio- Bile vessel.
cholecyst-, cholecysto- Gallbladder.
choledoch-, choledocho- Bile duct.
chondr-, chondro- Cartilage.
chrom-, chromo- Color.
-cide Causing death.
cine- Movement.
circum- Around.
clavicul-, claviculo- Clavicle.
-cle, -cule Little, e.g., molecule, corpuscle.
cleid-, cleido- Clavicle.
co-, com-, con- Together.
colp-, colpo- SEE: kolp-.

6. contra- Against; opposite.
crani-, cranio- Skull; cranium.
cry-, cryo- Cold.
-cusia,-cusis Hearing.
cyan-, cyano- Blue.
cycl-, cyclo- Circular; cyclical; ciliary body of the eye.
cyst-, cysto-, -cyst Cyst; urinary bladder.
cyt-, cyto-, -cyte Cell.
D
dacry- Tears.
dactyl-, dactylo- Finger; toe.
de- From; down; not.
dec-, deca- Ten.
deci- One tenth.
demi- Half.
dent-, denti-, dento- Teeth.
derm-, derma-, dermato-, dermo- Skin.
deuter-, deutero-, deuto- Second; secondary.
dextro- Right.
di- 1. Double; twice; two. 2. Apart from.
dia- Through; between; asunder.
dipla-, diplo- Double; twin.
dips-, dipso- Thirst.
dis- 1. Double; twice. 2. Negative; apart; absence of.

7. dors-, dorsi-, dorso- Back.
duoden-, duodeno- Duodenum.
-dynia Pain.
dys- Difficult; bad; painful.
E
-eal Pertaining to.
ec-, ecto- Out; on the outside.
-ectomy Excision.
ectro- Congenital absence of a part.
ef-, es-, ex-, exo- Out.
electr-, electro- Electricity.
embol-, embolo- Plug.
-emesis Vomiting.
-emia Blood.
en- In; into.
enantio- Opposite.
end-, endo- Within.
ent-, ento- Within; inside.
enter-, entero- Intestine.
ep-, epi- Upon; over; at; in addition to; after.
episi-, episio- Vulva.
erythr-, erythro- Red.
eschar-, escharo- Scab.
-esis SEE: -asis.

8. esophag-, esophago- Esophagus.
-esthesia Sensation.
etio- Causation.
eu- Well; good; healthy; normal.
eury- Broad.
ex- Out; away from; completely.
exo- Out; outside of; without.
extra- Outside of; in addition; beyond.
F
-facient Causing; making happen.
femor-, femoro- Thigh.
-ferous Producing.
ferri-, ferro- Iron.
fibro- Fibers; fibrous tissues.
fluo- Flow.
fluor-, fluoro- Luminous; fluorescence.
fore- Before; in front of.
-form Form.
-fuge To expel; to drive away; fleeing.
G
galact-, galacto- Milk.
gam-, gamo- Marriage; sexual union.
gaster-, gastero-, gastr-, gastro- Stomach.
gen- Producing; forming.
-gen, -gene, -genesis, -genetic, -genic Producing;

9. forming.
glauc-, glauco- Gray.
genito- Organs of reproduction.
gero- Old age.
giga- Billion.
gingiv-, gingivo- Gums (of the mouth).
-globin Protein.
gloss-, glosso- Tongue.
gluc-, gluco-, glyc-, glyco- Sugar; glycerol or similar
substance.
gnath-, gnatho- Jaw; cheek.
-gog, -gogue Make flow.
gon-, gono- Semen; seed; genitals; offspring.
-gram A tracing; a mark.
-graph Instrument for drawing or recording.
-graphy Writing; record.
-gravida Pregnant.
gyn-, gyne-, gyneco-, gyno- Woman; female.
gyro- Circle; spiral; ring.
H
hem-, hema-, hemato-, hemo- Blood.
hemi- Half.
hepat-, hepato- Liver.
heredo- Heredity.
heter-, hetero- Other; different.

10. hex-, hexa- Six.
histo- Tissue.
hol-, holo- Complete; entire; homogeneous.
homeo- Likeness; resemblance; constant, unchanging
state.
homo- Same; likeness.
hydra-, hydro-, hydr- Water.
hyo- Hyoid bone.
hyp-, hyph-, hypo- Less than; below or under; beneath;
deficient.
hyper- Above; excessive; beyond.
hypno- Sleep; hypnosis.
hyster-, hystero- Uterus.
I
-ia Condition, esp. an abnormal state.
-iasis SEE: asis.
-iatric Medicine; medical profession; physicians.
-ic Pertaining to; relating to.
ichthyo- Fish.
-id Secondary skin eruption distant from primary
infection site.
ideo- Mental images.
idio- Individual; distinct.
ileo- Ileum.

11. ilio- Ilium; flank.
im- SEE: in-. Used before b,m, or p.
immun-, immuno- Immune; immunity.
in- In; inside; within; intensive action; negative.
infra- Below; under; beneath; inferior to; after.
inter- Between; in the midst.
intra-, intro- Within; in; into.
ipsi- Same; self.
irid-, irido- Iris.
ischio- Ischium.
-isis SEE: -asis.
-ism Condition; theory.
iso- Equal.
-ite 1. Of the nature of. 2. In chemistry, a salt of an acid
with the termination -ous .
-itis Inflammation of.
-ize To treat by special method.
J
jejuno- Jejunum.
juxta- Close proximity.
K
kary-, karyo-, cary-, caryo- Nucleus; nut.
kat-, kata- SEE: cat-.

12. kera-, kerato- Horny substance; cornea.
ket-, keto- Ketone bodies (acids and acetones).
kilo- Thousand.
kinesi-, kino-, -kinesis Movement.
klepto- To steal.
kolp-, kolpo-, colp-, colpo- Vagina.
kypho- Humped.
kysth-, kystho- Vagina.
L
lab-, labi- Lip.
lact- Milk.
laparo- Flank; abdominal wall.
laryng-, laryngo- Larynx.
latero- Side.
leio- Smooth.
lepido- Flakes; scales.
-lepsy Seizure.
lepto- Thin; fine; slight; delicate.
leuk-, leuko-, leuc- White; white blood cell.
linguo- Tongue.
lip-, lipo- Fat.
-lite, -lith, lith-, litho- Stone; calculus.
-logia, -logy Science of; study of.
lord-, lordo- Curve; swayback.

13. lumbo- Loins.
lyo- Loosen; dissolve.
-lysis 1. Loosen; dissolve. 2. In medicine, reduction of;
relief from.
M
macr-, macro- Large; long.
mal- Ill; bad; poor.
mamm-, mammo- Breast.
-mania Frenzy; madness.
mast-, masto- Breast.
meat-, meato- Opening; meatus.
med-, medi-, medio- Middle.
medull-, medullo- Soft inner part; medulla.
mega-, megal-, megalo- Large; of great size.
-megalia, -megaly Enlargement of a body part.
meio-, mio- Less; smaller.
melan-, melano- Black.
mening-, meningo- Meninges.
menta-, mento- Mind.
mes-, meso- 1. Middle. 2. In anatomy, the mesentery. 3.
In medicine, secondary; partial.
mesio- Toward the middle.
meta- 1. Change; transformation; next in a series. 2. In
chemistry, the 1,3 position of benzene derivatives.
metacarp-, metacarpo- Metacarpus (bones of the

14. hand).
-meter Measure.
metr-, metra-, metro- Uterus.
micr-, micro- Small.
mio- SEE: meio-.
mon-, mono- Single; one.
muc-, muci-, muco-, myxa-, myxo- Mucus.
multi- Many; much.
musculo-, my-, myo- Muscle.
my-, myo- SEE: musculo-.
myc-, myco- Fungus.
myel-, myelo- Spinal cord; bone marrow.
myring-, myringo- Tympanic membrane, eardrum.
myx-, myxo- SEE: muc-.
N
nano- 1. One billionth. 2. Dwarfism (nanism).
narco- Numbness; stupor.
naso- Nose.
necr-, necro- Death; necrosis.
neo- New; recent.
nephr-, nephra-, nephro- Kidney.
neur-, neuri-, neuro- Nerve; nervous system.

15. nitr-, nitro- Nitrogen.
non- No.
normo- Normal; usual.
noso- Disease.
noto- The back.
nucleo- Nucleus.
nyct-, nycto- Night; darkness.
O
ob- Against.
occipit-, occipito- Occiput.
octa-, octo- Eight.
oculo- Eye.
-ode, -oid Form; shape; resemblance.
odont-, odonto- Tooth; teeth.
-odynia, odyno- Pain.
-oid SEE: -ode.
oleo- Oil.
olig-, oligo- Few; small.
-ology Science of; study of.
-oma Tumor.
omo- Shoulder.
omphal-, omphalo- Navel.
onco- Tumor; swelling; mass.
onych-, onycho- Fingernails; toenails.

16. oo-, ovi-, ovo- Egg; ovum.
oophor-, oophoro-, oophoron- Ovary.
ophthalm-, ophthalmo- Eye.
-opia Vision.
opisth-, opistho- Backward.
-opsy View of.
optico-, opto- Eye; vision.
orchi-, orchid-, orchido- Testicle.
-orexia Appetite.
oro- Mouth.
orth-, ortho- Straight; correct; normal; in proper order.
os- Mouth; bone.
oscheo- Scrotum.
-ose 1. Carbohydrate. 2. Primary alteration of a protein.
-osis Condition; status, process; abnormal increase.
osmo- 1. Odor; smell. 2. Impulse. 3. Osmosis.
oste-, osteo- Bone.
-ostomosis, -ostomy, -stomosis, -stomy A created
mouth or outlet.
ot-, oto- Ear.
-otomy Cutting.
-ous 1. Possessing; full of. 2. Pertaining to.
ovi-, ovo- SEE: oo-.
ox- Oxygen.

17. oxy- 1. Sharp; keen; acute; acid; pungent. 2. Oxygen in
a compound. 3. Hydroxyl group.
P
pach-, pachy- Thick.
-pagus Twins joined at a specific site, e.g., craniopagus.
pali-, palin- Recurrence; repetition.
pan- All; entire.
pant-, panto- All or the whole of something.
papulo- Pimple; papule.
para-, -para 1. Prefix: near; alongside of; departure from
normal. 2. Suffix: Bearing offspring.
patell-, patello- Patella; kneecap.
path-, patho-, -path, -pathic, -pathy Disease; suffering.
ped-, pedi-, pedo- Foot.
pedia- Child.
pedicul-, pediculo- Louse.
-penia Decrease from normal; deficiency.
pent-, penta- Five.
-pepsia Digestion.
per- Throughout; through; utterly; intense.
peri- Around; about.
perineo- Perineum.
peritoneo- Peritoneum.
pero- Deformed.
petro- 1. Stone. 2. The petrous portion of the temporal

18. bone.
-pexy Fixation, usually surgical.
phaco- Lens of the eye.
phag-, phago- Eating; ingestion; devouring.
phalang-, phalango- Phalanges (bones of fingers and
toes).
phall- Penis.
pharmaco- Drug; medicine.
pharyng-, pharyngo- Pharynx.
-phasia Speech.
-phil, -philia, -philic Love for; tendency toward; craving
for.
phlebo- Vein.
-phobia Abnormal fear or aversion.
phono- Sound; voice.
-phoresis Transmission.
-phoria In ophthalmology, a turning with reference to the
visual axis.
photo- Light.
phren-, phreno-, -phrenia 1. Mind. 2. Diaphragm.
-phylaxis Protection.
physico- Physical; natural.
physio- Pertaining to nature.
physo- Air; gas.
phyt-, phyto- Plant; something that grows.

19. pico- One trillionth.
picr-, picro- Bitter.
-piesis Pressure.
pimel-, pimelo- Fat.
plagio- Slanting; oblique.
-plakia Plaque.
-plasia Growth; cellular proliferation.
plasm-, -plasm 1. Prefix: Living substance or tissue. 2.
Suffix: To mold.
-plastic 1. Molded. 2. Restoration of lost or badly
formed features.
platy- Broad.
-plegia Paralysis; stroke.
pleur-, pleuro- Pleura; side; rib.
-ploid Chromosome pairs of a specific number.
plur-, pluri- Several; more.
pneo- Breath; breathing.
pneum-, pneuma-, pneumato- Air; gas; respiration.
pneumo-, pneumono- Air; lung.
pod-, podo- Foot.
poikil-, poikilo- Varied, irregular.
-poiesis, -poietic Production; formation.
polio- Gray matter of the nervous system.
poly- Much; many.
post- After.

20. postero- Posterior; behind; toward the back.
-praxis 1. Act; activity. 2. Practice; use.
pre- Before; in front of.
presby- Old age.
pro- Before; in behalf of.
proct-, procto- Anus; rectum.
proso- Forward, anterior.
prostat-, prostato- Prostate gland.
proto- 1. First. 2. In chemistry, the lowest of a series of
compounds with the same elements.
pseud-, pseudo- False.
psych-, psycho- Mind; mental processes.
psychro- Cold.
-ptosis Prolapse, downward displacement.
pubio-, pubo- Pubic bone or region.
pulmo- Lung.
py-, pyo- Pus.
pycn-, pycno-, pykn-, pykno- Dense; thick; compact;
frequent.
pyelo- Pelvis.
pyg-, pygo- Buttocks.
pykn-, pykno- SEE: pycn-.
pyle- Orifice, esp. of the portal vein.
pyloro- Gatekeeper, i.e., the pylorus.

21. pyreto- Fever.
pyro- Heat; fire.
Q-S
quadr-, quadri- Four.
quinqu- Five.
rachi-, rachio- Spine.
radio- 1. Radiant energy; a radioactive substance. 2. In
chemistry, a radioactive isotope.
re- Back; again.
recto- Straight; rectum.
ren-, reno- Kidney.
reticulo- Reticulum.
retro- Backward; back; behind.
rhabdo- Rod.
rheo-, -(r)rhea Current; stream; to flow; to discharge.
rhino- Nose.
rhizo- Root.
rhodo- Red.
roseo- Rose-colored.
-(r)rhage, -(r)rhagia Rupture; profuse fluid discharge.
-(r)rhaphy A suturing or stitching.
-(r)rhexis Rupture of a specific body part.
sacchar-, saccharo- Sugar.
sacro- Sacrum.
salping-, salpingo- Auditory tube; fallopian tube.

22. sapro- Putrid; rotten.
sarco- Flesh.
scapho- Boat-shaped; scaphoid.
scapulo- Shoulder.
scato- Dung; fecal matter.
schisto- Split; cleft.
schizo- Division.
scirrho- Hard; hard tumor or scirrhus.
sclero- 1. Hard. 2. Relating to the sclera.
-sclerosis Dryness; hardness.
-scope Instrument for viewing or examining (includes
other methods of examination).
-scopy Examination.
scoto- Darkness.
sebo- Fatty substance.
semi- Half.
septi- Seven.
sero- Serum.
sesqui- One and one half.
sial-, sialo- Saliva.
sidero- Iron; steel.
-sis SEE: -asis.
sitio-, sito- Bread; made from grain; food.
skeleto- Skeleton.

23. skia- Shadow.
sodio- Sodium.
somat-, somato- Body.
spectro- Appearance; image; form; spectrum.
sperma-, spermat-, spermato- Sperm; spermatozoa.
spheno- Wedge; sphenoid bone.
sphygmo- Pulse.
spir-, spiro- Breathe.
spleno- Spleen.
spondyl-, spondylo- Vertebra.
spongio- Spongelike.
staphylo- Uvula; bunch of grapes; Staphylococcus.
steato- Fat.
steno- Narrow; short.
sterco- Feces.
stere-, stereo- Three-dimensional.
sterno- Sternum.
stetho- Chest.
stomato- Mouth.
-stomosis, -stomy SEE: -ostomosis.
strepto- Twisted.
sub- Under; beneath; in small quantity; less than
normal.
super- Above; beyond; superior.

24. supra- Above; beyond; on top.
syn-, sym- With; together with; along; beside.
T
tachy- Swift; rapid.
taen-, taeni-, ten-, teni- Tapeworm.
tarso- 1. Flat of the foot. 2. Edge of the eyelid.
tauto- Same.
techno- Art; skill.
tel-, tele- 1. End. 2. Distant.
teleo- Perfect; complete.
temporo- Temples of the head.
ten-, teni- SEE: taen-.
tendo-, teno- Tendon.
ter- Three.
tera- One trillionth.
terato- Severely malformed fetus.
tetra- Four.
thalamo- Chamber; part of the brain where a nerve
originates; thalamus.
thanato- Death.
theco- Sheath; case; receptacle.
thermo- Hot; heat.
thio- Sulfur.
thorac-, thoraci-, thoraco- Chest; chest wall.

25. thrombo- Blood clot; thrombus.
thymo- 1. Thymus. 2. Soul; emotions.
thy-, thyro- Thyroid gland; oblong; shield.
thyroid-, thyroido- Thyroid gland.
toco- Childbirth.
-tome Cutting instrument.
tomo- Section; layer.
-tomy Cutting operation; excision.
ton-, tono- Tension.
top-, topo- Place; locale.
tox-, toxi-, toxico-, toxo-, -toxic Toxin; poison; toxic.
trachelo- Neck.
tracheo- Trachea; windpipe.
trans- Across; over; beyond; through.
traumato- Trauma.
tri- Three.
trich-, trichi-, tricho- Hair.
troph-, tropho-, -trophic Nourishment.
-tropin Stimulation of a target organ by a substance,
esp. a hormone.
tubo- Tube.
tympan-, tympano- Eardrum; tympanum.
typhlo- 1. Cecum. 2. Blindness.
typho- Fever; typhoid.
U-Z

26. ulo- Scar; scarring.
ultra- Beyond; excess.
uni- One.
uretero- Ureter.
urethro- Urethra.
-uria Urine.
urin-, urino-, uro- Urine.
uter-, utero- Uterus.
vagin-, vagino- Vagina.
varic-, varico- Dilated vein.
vaso- Vessel, e.g., blood vessel.
veno- Vein.
ventro-, ventr-, ventri- Abdomen; anterior surface of the
body.
vertebro- Vertebra; vertebrae.
vesico- Bladder; vesicle.
viscero- Viscera.
vitr-, vitro-, vitre-, vitreo- 1. Vitreous body (of the eye).
2. Glassy.
vulvo- 1. Vulva. 2. Covering.
xanth- Yellow.
xeno- Strange; foreign.
xero- Dry.
xiph-, xiphi-, xipho- Xiphoid cartilage.
zoo- Animal; animal life.