URL of this page: https://www.nlm.nih.gov/medlineplus/appendixa.html

Appendix A: Word Parts and What They Mean

Here is a list of word parts. They may be at the beginning, in the middle, or at the end of a medical word.

This appendix supplements the MedlinePlus Understanding Medical Words tutorial.

General Words

Part Definition
-ac pertaining to
andr-, andro- male
auto- self
bio- life
chem-, chemo- chemistry
cyt-, cyto- cell
-blast-, -blasto, -blastic bud, germ
-cyte, -cytic cell
fibr-, fibro- fiber
gluco-, glycol- glucose, sugar
gyn-, gyno-, gynec- female
hetero- other, different
hydr-, hydro- water
idio- self, one's own
-ity pertaining to
karyo- nucleus
neo- new
-ous pertaining to
oxy- sharp, acute, oxygen
pan-, pant-, panto- all or everywhere
pharmaco- drug, medicine
re- again, backward
somat-, somatico-, somato- body, bodily

Body Parts and Disorders

Part Definition
acous-, acouso- hearing
aden-, adeno- gland
adip-, adipo- fat
adren-, adreno- gland
angi-, angio- blood vessel
ateri-, aterio- artery
arthr-, arthro- joint
blephar- eyelid
bronch-, bronchi- bronchus  (large airway that leads from the trachea (windpipe) to a lung)
bucc-, bucco- cheek
burs-, burso- bursa (a small, fluid-filled sac that acts as a cushion between a bone and other moving parts)
carcin-, carcino- cancer
cardi-, cardio- heart
cephal-, cephalo- head
chol- bile
chondr- cartilage
Coron- heart
cost- rib
crani-, cranio- brain
cutane skin
cyst-, cysti-, cysto- bladder or sac
dactyl-, dactylo- digit (finger or toe)
derm-, dermato- skin
duodeno- duodenum (the first part of your small intestine, right after your stomach)
-esthesio sensation
gloss-, gloss- tongue
gastr- stomach
gnath-, gnatho- jaw
grav- heavy
hem, hema-, hemat-, hemato-, hemo- blood
hepat-, hepatico-, hepato- liver
hidr-, hidro- sweat
hist-, histio-, histo- tissue
hyster-, hystero- uterus
ileo- ileum (the lower part of the small intestine)
irid-, irido- iris
ischi-, ischio- ischium (the lower and back part of the hip bone)
-ium structure or tissue
kerat-, kerato- cornea (eye or skin)
lacrim-, lacrimo- tear (from your eyes)
lact-, lacti-, lacto- milk
laryng-, laryngo- larynx (voice box)
lingu-, linguo- tongue
lip-, lipo- fat
lith-, litho- stone
lymph-, lympho- lymph
mamm, mast-, masto- breast
mening-, meningo- meninges (the membranes that surround the brain and spinal cord)
muscul-, musclo- muscle
my-, myo- muscle
myel-, myelo- spinal cord OR bone marrow
myring-, myringo- eardrum
nephr-, nephro- kidney
neur-, neuri-, neuron nerve
oculo- eye
odont-, odonto- tooth
onych-, onycho- fingernail, toenail
oo- egg, ovary
oophor-, oophoro- ovary
op-, opt- vision
ophthalm-, ophthalmo- eye
orchid-, orchido-, orchio- testis
ossi- bone
osseo- bony
ost-, oste-, osteo- bone
ot-, oto- ear
ovari-, ovario-, ovi-, ovo- ovary
phalang- phalanx (any bone in the fingers or toes)
pharyng-, pharyngo- pharynx, throat
phleb-, phlebo- vein
phob-, phobia fear
phren-, phreni-, phrenico-, phreno- diaphragm
pleur-, pleura-, pleuro- rib, pleura (membrane that wraps around the outside of your lungs and lines the inside of your chest cavity)
pneum-, pneuma-, pneumat-, pneumato- air, lung
pod-, podo foot
prostat- prostate
psych-, psyche-, psycho- mind
proct-, procto- anus, rectum
pyel-, pyelo- pelvis
rachi- spine
rect-, recto- rectum
ren-, reno- kidney
retin- retina (of the eye)
rhin-, rhino- nose
salping-, salpingo- tube
sial-, sialo- saliva, salivary gland
sigmoid-, sigmoido- sigmoid colon
splanchn-, splanchni-, splanchno- viscera (internal organ)
sperma-, spermato-, spermo- sperm
spirat- breathe
splen-, spleno- spleen
spondyl-, spondylo- vertebra
stern- sternum (breastbone)
stom-, stoma-, stomat-, stomato- mouth
thel-, thelo- nipples
thorac-, thoracico-, thoraco- chest
thromb-, thrombo- blood clot
thyr-, thyro- thyroid gland
trache-, tracheo- trachea (windpipe)
tympan-, tympano- eardrum
ur-, uro- urine
uri-, uric-, urico- uric acid
-uria in the urine
vagin- vagina
varic-, varico- duct, blood vessel
vasculo- blood vessel
ven-, veno- vein
vertebr- vertebra, spine
vesic-, vesico- vesicle (cyst or pouch)

Positions and Directions

Part Definition
ab-, abs- away from
ambi- both sides
ante- before, forward
circum- around
cycl- circle, cycle
dextr-, dextro- right side
de- away from, ending
dia- across, through
ect-, ecto-, exo- outer; outside
en- inside
end-, endo-, ent- enter-, entero-, within; inner
epi- Upon, outside of
ex-, extra- beyond
infra- beneath; below
inter- between
intra- within
meso- middle
meta- beyond, change
para- alongside, abnormal
per- through
peri- around
post- behind, after
pre- before, in front
retro- backward, behind
sinistr-, sinistro- left, left side
sub- under
super- above
supra- above, upon
sy-. syl-, sym-, syn-, sys- together
trans- across, through

Numbers and Amounts

Part Definition
bi- two
brady- slow
diplo- double
hemi- half
homo- same
hyper- above, beyond, excessive
hypo- under, deficient
iso- equal, like
macro- large, long, big
meg-, mega-, megal-, megalo- great, large
-megaly enlargement
mic-, micro- small
mon-, mono- one
multi- many
olig-, oligo- few, little
poly- many, excessive
quadri- four
semi- half
tachy- fast
tetra- four
tri- three
uni- one

Color

Part Definition
chlor-, chloro- green
chrom-, chromato- color
Cyano- blue
erythr-, erythro- red
leuk-, leuko- white
melan-, melano- black
xanth-, xantho- yellow

Physical Properties and Shapes

Part Definition
-cele bulge 
elect- electrical activity
kin-, kine-, kinesi-, kinesio-, kino- movement
kyph-, kypho- humped
morph-, morpho- shape
rhabd-, rhabdo- rod-shaped, striated
scoli-, scolio- twisted
cry-, cryo- cold
phon-, phono- sound
phos- light
phot-, photo- light
reticul-, reticulo- net
therm-, thermo- heat
tono- tone, tension, pressure

Good and Bad

Part Definition
-alge-, -algesi pain
a-, an- without; lacking
anti- against
contra- against
dis- separation, taking apart
-dynia pain, swelling 
dys- difficult, abnormal 
-eal, -ial pertaining to
-ectasis expansion or dilation
-emesis vomiting
-emia blood condition
-esis state or condition
eu- good, well
-ia condition
-iasis condition, formation of   
-ism condition
-ites, -itis         inflammation
-lysis, -lytic, lyso-, lys- break down, destruction, dissolving
mal- bad, abnormal
-malacia softening
-mania morbid impulse towards an object/thing
myc-, myco- fungus
myx-, myxo- mucus
necr-, necro- death
normo- normal
-odyn pain
-oma tumor
-oid resembling
orth-, ortho- straight, normal, correct
-osis condition, usually abnormal
-pathy, patho-, path- disease  
-penia deficiency, lack of
-phagia, phagy eating, swallowing
-phasia speech
-plasia, -plastic growth
-plegia paralysis
-pnea breathing
-poiesis production
-praxia movement
pro- favoring, supporting
pseudo- false
pro- favoring, supporting
-ptosis falling, drooping
pyo- pus
pyro- fever
onco- tumor, bulk, volume
-rrhage, -rrhagic bleeding
-rrhea  flow or discharge
sarco- muscular, fleshlike
schisto- split, cleft, division
schiz-, schizo split, cleft
sclera-, sclero- hardness
-sclerosis hardening
-sis condition
-spasm muscle condition
spasmo- spasm
-stasis level, unchanging
sten-, steno- narrowed, blocked 
-taxis movement
-trophy growth

Procedures, Diagnosis and Surgery

Parts Definition
-centesis surgical puncture to remove fluid
-desis surgical binding
-ectomy cut out, removal  
-gram, -graph, -graphy recording, written
-meter device used for measuring
-metry measurement of
-opsy visual examination
-ostomy opening
-otomy Incision
-pexy surgical fixation
-plasty surgical reconstruction

radio-

radiation, radius

-rrhaphy suture
-scope, -scopy examine, for examining
-stomy surgical opening
-tomy cutting; incision
-tripsy crushing