Medword Resources
Medical Terminology Basics:
Prefixes Page 2

Prefixes, the most frequently used elements in the formation of Greek and Latin words, consist of one or more syllables (prepositions or adverbs) placed before words or roots to show various kinds of relationships. They are never used independently, but when added before verbs, adjectives, or nouns, they modify the meaning. Many prefixes are added to other words with a hyphen, but medical dictionary publishers are opting to drop the hyphen on many of the more common prefixed medical words.

Most prefixes are a part of words in ordinary speech and do not refer specifically to medical or scientific terminology, but there are many that occur frequently in medical terminology, and studying them is an important step in learning medical terms and building a medical vocabulary. You may also be interested in reviewing these Medword pages: Suffixes, USP Drug Listings, Basic Medical Terms, Examples of Transcribed Reports.

Prefix		Translation of Greek or Latin		Examples
Contra		Against, opposite		Contralateral (opposite side); contraception (prevention of conception); contraindicated (not indicated)
De		Away from		Dehydrate (remove water from); dedentition (removal of teeth); decompensation (failure of compensation)
Di		Twice, double		Diplopia (double vision); dichromatic (two colors); digastric (double stomach)
Dia		Through, apart, across, completely		Diaphragm (wall across); diapedesis (ooze through); diagnosis (complete knowledge)
Dis		Reversal, apart from, separation		Disinfection (apart from infection); disparity (apart from equality); dissect (cut apart)
Dys		Bad, difficult, disordered		Dyspepsia (bad digestion); dyspnea (difficult breathing); dystopia (disordered position)
E, ex		Out, away from		Enucleate (remove from); eviscerate (take out viscera or bowels); exostosis (outgrowth of bone)
Ec		Out from		Ectopic (out of place); eccentric (away from center); ectasia (stretching out or dilation)
Ecto		On outer side, situated on		Ectoderm (outer skin);ectoretina (outer layer of retina)
Em, en.		In		Empyema (pus in); encephalon (in the head)
Endo		Within		Endocardium (within heart); endometrium (within uterus)
Epi		Upon, on		Epidural (upon dura); epidermis (on skin)
Exo		Outside, on outer side, outer layer		Exogenous (produce outside); exocolitis (inflammation of outer coat of colon)
Extra		Outside		Extracellular (outside cell); extrapleural (outside pleura)
He mi		Half		Hemiplegia (partial paralysis); hemianesthesia (loss of feeling on one side of body)
Hyper		Over, above, excessive		Hyperemia (excessive blood); hypertrophy (over­growth); hyperplasia (excessive formation)
Hypo		Under, below, deficient		Hypotension (low blood pressure); hypothyroidism (deficiency or underfunction of thyroid)

  Continued . . .  

Prefixes ­ Page 1: "a" To "Con"
Prefixes ­ Page 3: "Im" To "Ultra"