Medical Terminology – Prefixes

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.

Prefix	Definition	Example
a-	Without; Lack of	Aphagia = Lack of eating
an-	Without; Lack of	Anesthesia = Without feeling
ab-	From; Away from	Abduct = Movement away from the midline of the body
ad-	Toward; Increase	Adduct = Movement toward the midline of the body
ambi-	Both; Both sides	Ambidextrous = Ability to use both hands equally
ante-	Before; In front	Antecubital = In front of the elbow
anti-	Against; Opposing	Antibiotics = “Opposing life;” A substance used against microbes
bi-	Two; Double	Bifocal = Two foci
bio-	Life	Biology = Study of life
brady-	Slow	Bradycardia = Slow heart rate
chlor/o-	Green	Chlorophyll = Green pigment in plants
circum-	Around	Circumflex = Curved around
con-	With; Together	Congenital = Born with
contra-	Against; Opposite	Contralateral = Opposite side
dia-	Through; Across; Completely	Diagnosis = Complete knowledge; Knowledge through testing
dis-	Free of; Undo; Reversal; Apart from; Separation	Dissect = To cut apart
dys-	Bad; Difficult; Painful	Dyspnea = Difficulty breathing
endo-	Within; Inner	Endoscopy = To examine within the body
epi-	Upon; Over	Epidermis = Outer layer of skin
hemi-	Half	Hemiplegia = Paralysis of half of the body
hetero-	Different	Heterozygous = Two different forms of a gene
homo-	Same	Homogeneous = Same composition/structure throughout
hyper-	Excessive; Above normal	Hypertension = High blood pressure
hypo-	Under; Below; Less than normal	Hypothermia = Below normal temperature
inter-	Between	Intercostal = Between the ribs
intra-	Within	Intravenous = Within the vein
jaund/o-	Yellow	Jaundice = Yellowing of the skin
meta-	Beyond; After	Metacarpal = Bones beyond the wrist
para-	Near; Beside; Beyond	Paracardiac = Beside the heart
peri-	Around	Periosteum = Around the bone
pre-	Before; In front of	Premaxillary = In front of the Maxilla
re-	Back; Again	Reactivate = To make active again
retro-	Backward; Located behind	Retrolingual = Behind the tongue
semi-	Half	Semiconscious = Half conscious
tachy-	Fast; Rapid	Tachycardia = Fast heart rate

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