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Most medical terms are built from reusable parts: a prefix, a root and a suffix. Learn the 140 most common word parts below and you can work out the meaning of thousands of medical terms — for example, peri (around) + card (heart) + itis (inflammation) = pericarditis, inflammation around the heart. Your progress is saved automatically!
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A prefix sits at the start of a word and typically describes location, direction, time, number or degree — like hyper- (excessive) in hypertension or brady- (slow) in bradycardia.
| a-, an- | Without, not, absence of. Examples: apnea (temporary absence of breathing); anuria (producing no urine); atypical (not typical). |
| ab- | Away from. Examples: abduction (movement of a limb away from the midline of the body). |
| ad- | Toward, near. Examples: adduction (movement of a limb toward the midline of the body). |
| ante- | Before, in front of. Examples: antenatal (before birth); antepartum (before labor). |
| anti- | Against. Examples: antibiotic (medicine that fights bacterial infection); anticoagulant (medicine that reduces blood clotting). |
| bi- | Two, both. Examples: bilateral (affecting both sides); bicornuate (having two horns, as in a heart-shaped uterus). |
| brady- | Slow. Examples: bradycardia (abnormally slow heart rate). |
| circum- | Around. Examples: circumoral (around the mouth); circumcision (surgical removal of the foreskin). |
| contra- | Against, opposite. Examples: contraception (prevention of pregnancy); contraindication (a reason not to use a particular treatment). |
| dys- | Difficult, painful or abnormal. Examples: dysmenorrhea (painful periods); dyspnea (difficulty breathing); dysuria (painful urination). |
| ecto- | Outside, out of place. Examples: ectopic (in an abnormal place, as in ectopic pregnancy). |
| endo- | Within, inner. Examples: endometrium (the inner lining of the womb); endoscopy (looking inside the body with a camera). |
| epi- | Upon, above, on top of. Examples: epidural (anesthetic injected on top of the outer membrane of the spinal cord); epidermis (the outer layer of the skin). |
| eu- | Good, normal. Examples: euthyroid (normal thyroid function); eupnea (normal, unlabored breathing). |
| hemi- | Half, one side. Examples: hemiplegia (paralysis of one side of the body). |
| hyper- | Excessive, above normal. Examples: hypertension (high blood pressure); hyperglycemia (high blood sugar). |
| hypo- | Deficient, below normal, under. Examples: hypotension (low blood pressure); hypoglycemia (low blood sugar). |
| inter- | Between. Examples: intercostal (between the ribs). |
| intra- | Within, inside. Examples: intravenous (into or within a vein); intrauterine (within the womb). |
| macro- | Large. Examples: macrosomia (a larger-than-average baby). |
| micro- | Small. Examples: microcephaly (an unusually small head); microscope (instrument for viewing very small objects). |
| multi- | Many. Examples: multigravida (a woman who has been pregnant more than once). |
| neo- | New. Examples: neonatal (relating to the first weeks after birth); neoplasm (an abnormal new growth of tissue). |
| pan- | All, entire. Examples: pancytopenia (reduced numbers of red cells, white cells and platelets in the blood). |
| para- | Beside, near. Examples: parathyroid (glands beside the thyroid); paraovarian (beside the ovary). |
| peri- | Around, surrounding. Examples: perinatal (around the time of birth); pericardium (the sac surrounding the heart). |
| poly- | Many, much, excessive. Examples: polyuria (passing unusually large amounts of urine); polycystic (having many cysts). |
| post- | After. Examples: postnatal (after birth); postoperative (after surgery). |
| pre- | Before. Examples: prenatal (before birth); premature (born before 37 weeks of pregnancy). |
| pseudo- | False. Examples: pseudocyesis (false pregnancy). |
| retro- | Behind, backward. Examples: retroverted (tilted backward, as of the womb). |
| sub- | Under, below. Examples: subcutaneous (under the skin). |
| supra- | Above. Examples: suprapubic (above the pubic bone). |
| tachy- | Fast, rapid. Examples: tachycardia (abnormally fast heart rate). |
| trans- | Across, through. Examples: transvaginal (through the vagina, as in a transvaginal scan); transfusion (transferring blood into the circulation). |
| tri- | Three. Examples: trimester (one of the three three-month periods of pregnancy). |
| ultra- | Beyond. Examples: ultrasound (sound waves beyond the audible range, used for scanning). |
| uni- | One, single. Examples: unilateral (affecting one side only). |
A suffix ends the word and usually describes a condition, procedure or disease process — like -itis (inflammation) in arthritis or -ectomy (surgical removal) in hysterectomy.
| -algesia | Sensitivity to pain. Examples: analgesia (loss or absence of pain); hyperalgesia (heightened sensitivity to pain). |
| -algia | Pain. Examples: neuralgia (nerve pain); myalgia (muscle pain). |
| -cele | Hernia, bulging or protrusion. Examples: cystocele (the bladder bulging into the wall of the vagina); rectocele (the rectum bulging into the wall of the vagina). |
| -centesis | Surgical puncture to remove fluid. Examples: amniocentesis (sampling the fluid around a baby in the womb); thoracentesis (draining fluid from around the lungs). |
| -cyte | Cell. Examples: erythrocyte (red blood cell); leukocyte (white blood cell). |
| -ectomy | Surgical removal. Examples: hysterectomy (removal of the womb); appendicectomy (removal of the appendix); oophorectomy (removal of an ovary). |
| -emia | Blood condition. (UK spelling: -aemia.) Examples: anemia (low level of hemoglobin in the blood); septicemia (serious blood infection). |
| -gen | Something that produces or forms. Examples: antigen (a substance that triggers an immune response); pathogen (an organism that causes disease); allergen (a substance that provokes an allergic reaction). |
| -genic | Producing, causing. Examples: carcinogenic (cancer-causing); pathogenic (disease-causing). |
| -gram | A record or image. Examples: mammogram (an X-ray image of the breast); cardiotocogram (a trace of a baby's heart rate and contractions). |
| -graphy | The process of recording or imaging. Examples: angiography (imaging the blood vessels); radiography (taking X-ray images). |
| -ism | Condition, state or process. Examples: embolism (blockage of a vessel by a clot or other plug); hyperthyroidism (an overactive thyroid gland). |
| -itis | Inflammation. Examples: arthritis (inflammation of the joints); dermatitis (inflammation of the skin); endometritis (inflammation of the lining of the womb). |
| -logy | The study of. Examples: gynecology (the study of women's reproductive health); cardiology (the study of the heart). |
| -logist | A specialist in the study of. Examples: gynecologist (specialist in women's reproductive health); hematologist (specialist in diseases of the blood). |
| -lysis | Breakdown, destruction, separation. Examples: hemolysis (breakdown of red blood cells); dialysis (filtering waste from the blood). |
| -malacia | Softening. Examples: osteomalacia (softening of the bones). |
| -megaly | Enlargement. Examples: hepatomegaly (enlarged liver); cardiomegaly (enlarged heart). |
| -oma | Tumor, mass or growth. Examples: carcinoma (a cancerous tumor); fibroma (a benign growth of fibrous tissue). |
| -osis | Abnormal condition or disease process. Examples: endometriosis (womb-lining cells growing outside the womb); thrombosis (a blood clot forming in a blood vessel); osteoporosis (bones becoming fragile). |
| -ostomy | Creating a surgical opening. Examples: colostomy (an opening of the colon onto the abdominal wall); tracheostomy (an opening into the windpipe). |
| -otomy | Surgical incision, cutting into. Examples: laparotomy (an incision into the abdomen); episiotomy (a cut made to widen the vaginal opening during birth). |
| -pathy | Disease. Examples: neuropathy (disease of the nerves); cardiomyopathy (disease of the heart muscle). |
| -penia | Deficiency, reduced number. Examples: thrombocytopenia (low level of platelets in the blood); osteopenia (reduced bone density). |
| -phagia | Eating, swallowing. Examples: dysphagia (difficulty swallowing). |
| -phasia | Speech. Examples: aphasia (loss of the ability to speak or understand speech). |
| -philia | Affinity for, tendency toward. Examples: hemophilia (an inherited tendency to bleed). |
| -phobia | Fear. Examples: claustrophobia (fear of enclosed spaces). |
| -plasia | Formation, growth of cells or tissue. Examples: dysplasia (abnormal cell growth); hyperplasia (increased cell growth). |
| -plasty | Surgical repair or reshaping. Examples: angioplasty (widening a narrowed blood vessel); rhinoplasty (reshaping the nose). |
| -plegia | Paralysis. Examples: paraplegia (paralysis of the legs); hemiplegia (paralysis of one side of the body). |
| -pnea | Breathing. (UK spelling: -pnoea.) Examples: apnea (pauses in breathing); dyspnea (difficulty breathing). |
| -rrhagia, -rrhage | Excessive flow, bursting forth. Examples: hemorrhage (very heavy bleeding); menorrhagia (very heavy periods). |
| -rrhea | Flow, discharge. (UK spelling: -rrhoea.) Examples: diarrhea (loose, watery stools); amenorrhea (absence of periods). |
| -rrhexis | Rupture. Examples: amniorrhexis (breaking of the waters before or during labor). |
| -sclerosis | Hardening. Examples: atherosclerosis (hardening and narrowing of the arteries). |
| -scope | Instrument for viewing or examining. Examples: laparoscope (camera instrument used in keyhole surgery); colposcope (microscope used to examine the cervix). |
| -scopy | Visual examination. Examples: colposcopy (examination of the cervix); laparoscopy (keyhole examination of the abdomen); hysteroscopy (examination of the inside of the womb). |
| -stasis | Stopping, controlling, standing still. Examples: hemostasis (stopping of bleeding). |
| -stenosis | Narrowing. Examples: pyloric stenosis (narrowing of the outlet of the stomach). |
| -tocia | Labor, birth. Examples: dystocia (difficult or abnormal labor). |
| -trophy | Growth, nourishment, development. Examples: atrophy (wasting or shrinking of tissue); hypertrophy (enlargement of tissue). |
| -uria | Condition of the urine. Examples: hematuria (blood in the urine); polyuria (passing large amounts of urine); dysuria (painful urination). |
The root carries the core meaning of the term, usually a body part or system — like cardi/o (heart) or hyster/o (womb). The “/o” is a combining vowel that joins the root to the next part of the word.
| abdomin/o | Abdomen. Examples: abdominal (relating to the abdomen). |
| angi/o | Blood vessel. Examples: angiography (imaging the blood vessels); angioplasty (widening a narrowed blood vessel). |
| arthr/o | Joint. Examples: arthritis (inflammation of the joints); arthroscopy (keyhole examination of a joint). |
| cardi/o | Heart. Examples: cardiology (the study of the heart); tachycardia (fast heart rate); cardiomegaly (enlarged heart). |
| cephal/o | Head. Examples: cephalhematoma (a bruise on a newborn baby's head); microcephaly (an unusually small head). |
| chron/o | Time. Examples: chronic (lasting a long time or keeps coming back); chronological (arranged in order of time). |
| col/o | Colon, large intestine. Examples: colostomy (an opening of the colon onto the abdominal wall); colitis (inflammation of the colon). |
| colp/o | Vagina. Examples: colposcopy (examination of the cervix through the vagina). |
| coron/o | Heart; a crown or encircling structure. Examples: coronary (relating to the arteries that encircle the heart). |
| cyst/o | Bladder, fluid-filled sac. Examples: cystitis (inflammation of the bladder); cystocele (the bladder bulging into the vaginal wall). |
| cyt/o | Cell. Examples: cytology (the study of cells). |
| derm/o, dermat/o | Skin. Examples: dermatitis (inflammation of the skin); dermatology (the study of skin conditions). |
| embol/o | Plug, obstruction. Examples: embolism (blockage of a vessel by a clot or other plug); embolus (the clot or material that blocks the vessel). |
| encephal/o | Brain. Examples: encephalitis (inflammation of the brain). |
| enter/o | Intestine. Examples: gastroenteritis (inflammation of the stomach and intestines). |
| gastr/o | Stomach. Examples: gastrointestinal (relating to the stomach and intestines); gastroenteritis (inflammation of the stomach and intestines). |
| gluc/o, glyc/o | Sugar, glucose. Examples: hyperglycemia (high blood sugar); hypoglycemia (low blood sugar); glucose (the main sugar the body uses for energy). |
| gynec/o | Woman, female. (UK spelling: gynaec/o.) Examples: gynecology (the study of women's reproductive health); gynecologist (specialist in women's reproductive health). |
| hem/o, hemat/o | Blood. (UK spelling: haem/o, haemat/o.) Examples: hemorrhage (very heavy bleeding); hematologist (specialist in diseases of the blood); hematuria (blood in the urine). |
| hepat/o | Liver. Examples: hepatitis (inflammation of the liver); hepatomegaly (enlarged liver). |
| hyster/o | Womb, uterus. Examples: hysterectomy (removal of the womb); hysteroscopy (examination of the inside of the womb). |
| immun/o | Immune, protected. Examples: immunity (protection against a disease); immunotherapy (treatment that works through the immune system); autoimmune (the immune system attacking the body's own tissue). |
| isch/o | To hold back, restrict. Examples: ischemia (reduced blood supply to a tissue); ischemic (affected by a reduced blood supply). |
| lapar/o | Abdomen, abdominal wall. Examples: laparoscopy (keyhole examination of the abdomen); laparotomy (an incision into the abdomen). |
| lip/o | Fat, lipid. Examples: lipoprotein (a particle that carries fat through the blood); liposuction (removal of fat by suction). |
| mamm/o | Breast. Examples: mammogram (an X-ray image of the breast). |
| muscul/o | Muscle. Examples: muscular (relating to the muscles); musculoskeletal (relating to the muscles and the skeleton). |
| my/o | Muscle. Examples: myometrium (the muscle wall of the womb); myalgia (muscle pain). |
| nat/o | Birth. Examples: prenatal (before birth); neonatal (relating to the first weeks after birth); postnatal (after birth). |
| nephr/o | Kidney. Examples: nephritis (inflammation of the kidneys); nephrology (the study of the kidneys). |
| neur/o | Nerve. Examples: neuralgia (nerve pain); neurology (the study of the nervous system). |
| oophor/o | Ovary. Examples: oophorectomy (removal of an ovary). |
| ophthalm/o | Eye. Examples: ophthalmology (the study of the eyes). |
| oste/o | Bone. Examples: osteoporosis (bones becoming fragile); osteomalacia (softening of the bones). |
| path/o | Disease. Examples: pathology (the study of disease); pathogenic (disease-causing). |
| pelv/i | Pelvis, the bony basin of the hips. Examples: pelvic (relating to the pelvis); pelvimetry (measurement of the pelvis). |
| phleb/o | Vein. Examples: phlebitis (inflammation of a vein); phlebotomy (drawing blood from a vein). |
| plasm/o | Plasma; formed or moulded substance. Examples: plasma (the liquid part of blood); cytoplasm (the material inside a cell). |
| pneum/o, pneumon/o | Lung, air. Examples: pneumonia (infection and inflammation of the lungs); pneumothorax (air trapped between the lung and chest wall). |
| por/o | Passage, pore, opening. Examples: osteoporosis (bones becoming porous and fragile). |
| prostat/o | Prostate gland. Examples: prostatectomy (removal of the prostate); prostatitis (inflammation of the prostate). |
| psych/o | Mind. Examples: psychology (the study of the mind and behavior); psychiatrist (doctor specializing in mental health). |
| pulmon/o | Lung. Examples: pulmonary embolus (a blood clot in the lung). |
| rect/o | Rectum. Examples: rectocele (the rectum bulging into the wall of the vagina); rectal (relating to the rectum). |
| ren/o | Kidney. Examples: renal (relating to the kidneys). |
| rhin/o | Nose. Examples: rhinoplasty (reshaping the nose); rhinorrhea (a runny nose). |
| salping/o | Fallopian tube. Examples: salpingectomy (removal of a fallopian tube); hysterosalpingogram (an X-ray of the womb and fallopian tubes). |
| skelet/o | Skeleton, the body's framework of bones. Examples: skeletal (relating to the skeleton); musculoskeletal (relating to the muscles and the skeleton). |
| spin/o | Spine, backbone. Examples: spinal (relating to the spine). |
| thromb/o | Blood clot. Examples: thrombosis (a blood clot forming in a blood vessel); thrombocytopenia (low level of platelets in the blood). |
| thyroid/o, thyr/o | Thyroid gland. Examples: thyroiditis (inflammation of the thyroid gland); hyperthyroidism (an overactive thyroid gland). |
| tox/o | Poison, toxin. Examples: toxemia (toxins in the blood); cytotoxic (damaging to cells). |
| urethr/o | Urethra, the tube that carries urine out of the body. Examples: urethritis (inflammation of the urethra); transurethral (through the urethra). |
| ur/o | Urine, urinary tract. Examples: urology (the study of the urinary tract); urodynamics (tests of how the bladder works). |
| uter/o | Womb, uterus. Examples: intrauterine (within the womb); uterine (relating to the womb). |
| vagin/o | Vagina. Examples: vaginitis (inflammation of the vagina); vaginosis (an imbalance of the bacteria in the vagina). |
| vascul/o | Blood vessel. Examples: vascular (relating to the blood vessels); cardiovascular (relating to the heart and blood vessels). |
| vas/o | Vessel, duct. Examples: vasectomy (cutting the tubes that carry sperm); vasoconstriction (narrowing of blood vessels). |
| vertebr/o | Vertebra, a bone of the spine. Examples: vertebral (relating to the vertebrae); intervertebral (between the vertebrae). |
Once you know the building blocks, test yourself on complete terms with the medical terminology flashcard quiz or look terms up in the A–Z glossary of medical terms.