Medical Terminology – Prefixes

PACS Training - Medical Basics 101

A prefix comes at the beginning of the word and usually modifies the meaning of the word root. Let’s see an example of how prefixes do this:

  • Glycemia is a medical term that means, “presence of glucose in the blood.”
    • Word Root = Glyc/o = glucose/sugar
    • Suffix = -emia = present in blood
  • Now let’s add a prefix to this term:
    • Hyperglycemia = Excessive or above normal level of glucose/sugar present in the blood.
    • Hypoglycemia = Less than normal level of glucose/sugar present in the blood.

Do you see how a prefix can change the definition of the medical term without modifying the meaning of the word root? Once attached to a medical term, they can express quantity, measurements, position, color, and much more. 

The rest of this module will list common prefixes that are used in general context.

PrefixDefinitionExample
a- Without; Lack ofAphagia = Lack of eating
an- Without; Lack ofAnesthesia = Without feeling
ab-From; Away fromAbduct = Movement away from the midline of the body
ad-Toward; IncreaseAdduct = Movement toward the midline of the body
ambi-Both; Both sidesAmbidextrous = Ability to use both hands equally
ante-Before; In frontAntecubital = In front of the elbow
anti-Against; OpposingAntibiotics = “Opposing life;” A substance used against microbes
bi-Two; DoubleBifocal = Two foci
bio-LifeBiology = Study of life
brady-SlowBradycardia = Slow heart rate
chlor/o-GreenChlorophyll = Green pigment in plants
circum-AroundCircumflex = Curved around
con-With; TogetherCongenital = Born with
contra-Against; OppositeContralateral = Opposite side
dia-Through; Across; CompletelyDiagnosis = Complete knowledge; Knowledge through testing
dis-Free of; Undo; Reversal; Apart from; SeparationDissect = To cut apart
dys-Bad; Difficult; PainfulDyspnea = Difficulty breathing
endo-Within; InnerEndoscopy = To examine within the body
epi-Upon; OverEpidermis = Outer layer of skin
hemi-HalfHemiplegia = Paralysis of half of the body
hetero-DifferentHeterozygous = Two different forms of a gene
homo-SameHomogeneous = Same composition/structure throughout
hyper-Excessive; Above normalHypertension = High blood pressure
hypo-Under; Below; Less than normalHypothermia = Below normal temperature
inter-BetweenIntercostal = Between the ribs
intra-WithinIntravenous = Within the vein
jaund/o-YellowJaundice = Yellowing of the skin
meta-Beyond; AfterMetacarpal = Bones beyond the wrist
para-Near; Beside; BeyondParacardiac = Beside the heart
peri-AroundPeriosteum = Around the bone
pre-Before; In front ofPremaxillary = In front of the Maxilla
re-Back; AgainReactivate = To make active again
retro-Backward; Located behindRetrolingual = Behind the tongue
semi-HalfSemiconscious = Half conscious
tachy-Fast; RapidTachycardia = Fast heart rate

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