You are here
Home > Medical Terminology > Medical Terminology Reference – O


[ 1 ] Quick Introduction.

[ 2 ] Word Building Reference: new icon   This is a great reference to help strengthen your understanding of medical terminology.   See how common medical terms are created using the various prefixes, suffixes, and root words.

[ 3 ]  Medical Terms – Singular versus plural rules

[ 4 ]  Medical Terminology Exams  new icon   Twenty new exams were created to test your knowledge of medical terminology.

[ 5 ]  Medical Terms – Prefixes, roots, suffixes (see links below)

Prefix: A prefix is placed at the beginning of a word to modify or change its meaning. Pre means “before.” Prefixes may also indicate a location, number, or time.
Root: central part of a word.
Suffix: The ending part of a word that modifies the meaning of the word.
Example: cholecystitis. Root = ‘cholecyst/o’ -Definition: gallbladder and the suffix is ‘itis’ – Definition: inflammation. Translation: inflammation of the gallbladder.

Alphabetical Listing of Med Terms

a b c d e f g h i j k l m
n o p q r s t u v w x y z

Medical Terminology Reference – O

obstetr/o   pregnancy; birth
ocul/o   eye
odont/o   tooth
odyn/o   pain
-oid   resembling; derived from
-ole   little; small
ole/o   oil
olecran/o   olecranon (elbow)
olig/o   scanty
om/o   shoulder
-oma   tumor; mass; fluid collection
omphal/o   umbilicus (navel)
onc/o   tumor
-one   hormone
one   mono, uni
one and a half   bi, di
onych/o   nail (of fingers or toes)
o/o   egg
oophor/o   ovary
-opaque   obscure
ophry/o   eyebrow
ophthalm/o   eye
-opia   vision condition
opisth/o   backward, behind
-opsia   vision condition
-opsy   view of
opt/o   eye; vision
optic/o   eye; vision
-or   one who
or/o   mouth
orch/o   testis
orchi/o   testis
orchid/o   testis
-orexia   appetite
organ/o   organ
orth/o   straight
osche/o   scrotum
-ose   full of; pertaining to; sugar
-osis   condition, usually abnormal
-osmia   smell
osphresi/o   sense of smell
ossicul/o   ossicle (small bone)
oste/o   bone
-ostosis   condition of bone
ot/o   ear
-otia   ear condition
-ous   pertaining to
ov/o   egg
ovari/o   ovary
ovul/o   egg
ox/o   oxygen
-oxia   oxygen
oxy-   swift; sharpp; acid
oxysm/o   sudden


The authors make no claims of the accuracy of the information contained herein; and these suggested doses are not a substitute for clinical judgment. Neither GlobalRPh Inc. nor any other party involved in the preparation of this program shall be liable for any special, consequential, or exemplary damages resulting in whole or part from any user’s use of or reliance upon this material.PLEASE READ THE DISCLAIMER CAREFULLY BEFORE ACCESSING OR USING THIS SITE. BY ACCESSING OR USING THIS SITE, YOU AGREE TO BE BOUND BY THE TERMS AND CONDITIONS SET FORTH IN THE DISCLAIMER. Read the disclaimer