1 Identifying Word Parts in Medical Terms

Welcome to Medical Terminology. Medical terminology is a language that is used in health care settings. Medical terms are built from Greek and Latin word parts and in addition include acronyms, such as “laser” (light amplification by stimulated emission of radiation), eponyms, such as West Nile Virus (named after a geographical location where the virus was identified) or Alzheimer disease (named after the person who discovered it) and modern-day language terms, such as “nuclear medicine scanner”, which is derived from the English language.

Word Parts

Medical terms are built from four word parts. Those word parts are prefix, word root, suffix, and combining vowel. When a word root is combined with a combining vowel, the word part is referred to as a combining form.

Word Root

The word root contains the fundamental meaning of the word. It is the core part of the word. Each medical term contains at least one word root.


  • In the word:  play/er (play is the word root)
  • In the medical term:   arthr/itis (arthr – meaning “joint” – is the word root)
Some words contain more than one word root. The order is generally dictated by common practice. As you practice throughout this course, you will learn more about how to determine the order of word roots.


Prefixes are located at the beginning of a medical term. The prefix alters the meaning of the medical term. It is important to spell and pronounce prefixes correctly.


  • In the word: re/play (“re” is the prefix)
  • In the medical term: intra/ven/ous (“intra” is the prefix)

Many prefixes that you find in medical terms are common to English language prefixes. A good technique to help with memorization is the following:

  • Start by reviewing the most common prefixes.
  • Consider common English language words that begin with the same prefixes.
  • Compare them to the examples of use in medical terms.

Prefixes often indicate:

  • Number: such as bi-meaning two
  • Position: such as sub-, meaning under
  • Direction: such as intra-, meaning within
  • Time: such as brady-, meaning slow
  • Negation: such as a- and an-, meaning without


Suffixes are word parts that are located at the end of words. Suffixes can alter the meaning of medical terms. In order to properly spell and pronounce medical terms, it is helpful to learn the suffixes.


  • In the word: king/dom (“-dom” is the suffix)
  • In the medical term: hepat/itis (“-itis” is the suffix)

When defining a medical term you often begin with the meaning of the suffix. For example: hepat/itis would be defined as “inflammation of the liver.”

Suffixes often indicate:

  • Procedures: such as -scopy, meaning visual examination
  • Conditions: such as -itis, meaning inflammation
  • Diseases: such as -oma, meaning tumor

Combining Vowel

The combining vowel is a word part – most often an o – that helps pronunciation.

The combining vowel is placed to connect two word roots or to connect a word root and a suffix. Do NOT place a combining vowel to connect a prefix and a word root. Not all medical terms will have combining vowels.

Table 1.1 Combining Vowel Guidelines

Guideline Example
1. When connecting a word root and a suffix, a combining vowel is used if the suffix DOES NOT begin with a vowel arthr/o/pathy
2. When connecting a word root and a suffix, a combining vowel is usually NOT USED if the suffix BEGINS with a vowel hepat/ic
3. When connecting two word roots, a combining vowel is usually used even if vowels are present at the junction oste/o/arthr/itis
4. When connecting a prefix and a word root, a combining vowel is NOT USED sub/hepat/ic


Categories of Medical Terms

All medical terms are divided into two basic categories:

  1. terms built from word parts
  2. terms NOT built from word parts

Table: 1.2 Categories of Medical Terms

Category Origin Example Learning Method
Terms Built from Word Parts Word parts of Greek and Latin origin combined to create literal translations 1. cytogenic

2. dysplasia

1. Analyzing terms

2. Defining terms

3. Building terms

Terms NOT built from Word Parts 1. Eponyms

2. Acronyms

3. Modern Language

4. Terms from Greek and Latin word parts that cannot be easily translated to find their meanings

1. Parkinson’s Disease

2. AIDS (acquired immunodeficiency syndrome)

3. posttraumatic stress disorder

4. orthopedics

1. Recalling terms

2. Matching terms

3. Defining terms


Medical terms are also further divided into:

  1. Disease and Disorder – These are terms that describe any harmful deviation from the normal structural or functional state of an organism, generally associated with certain signs and symptoms. It does not include physical injury. An example of a disease is bronchopneumonia, which is a diseased state of the bronchi and lungs.
  2. Diagnostic/Procedural – These are terms related to the process of identifying a disease, condition, or injury from its signs and symptoms. An example of a diagnostic term is transrectal ultrasound, which is an ultrasound procedure used to diagnose prostate cancer.
  3. Therapeutic – These are terms regarding treating or curing of diseases. An example of a therapeutic term is nebulizer, which is a device that creates a mist used to deliver medication for respiratory treatment.
  4. Anatomical – These are terms used to describe specific areas and movement of the body as well as the relation of body parts to each other. An example of an anatomical term is medial, which describes the middle or direction toward the middle of the body.

Language Rules

Language rules are a good place to start when building a medical terminology foundation.  Many medical terms are built from word parts and can be translated literally. At first, literal translations sound awkward. Once you build a medical vocabulary and become proficient at using it, the awkwardness will slip away. For example, suffixes will no longer be stated and will be assumed. The definition of intravenous then becomes within the vein.

Since you are at the beginning of building your medical terminology foundation stay literal when applicable. It should be noted that as with all language rules there are always exceptions and we refer to those as rebels.

By the end of this resource, you will have identified hundreds of word parts within medical terms.  Here are some common medical terms that many non-medically trained people may be familiar with.


Oste/o/arthr/itis – Inflammation of bone and joint.

Oste/o is a combining form that means bone
arthr/o is a combining form that means joint
-itis is a suffix that means inflammation

Intra/ven/ous – Pertaining to within a vein.
Intra- is a prefix that means within
ven/o – is a combining form that means vein
-ous is a suffix that means pertaining to

When breaking down words place slashes between word parts and a slash on each side of a combining vowel. Notice how the term is defined by beginning with the meaning of the suffix, then shifts to the beginning of the term with the meaning of the word parts in the order they appear.


Special marking above vowels indicate the proper pronunciation of the vowel. When you see a macron (or straight line) above the vowel, that means the vowel sound is long. A u-shaped symbol above a vowel indicates a short vowel sound. CAPITAL letters indicate where to place the emphasis when pronouncing a word. The table below provides examples, try pronouncing them aloud.

Table 1.3 Combining Vowels Tips

Guidelines Examples
1. Words are distorted minimally to indicate the proper phonetic sound. doctor (dŏk-tŏr)
2. The macron (line above the letter) indicated a long vowel sound. prorate (prō-rāt)

As in the:

ā in play

ē in be

ī in wine

ō in go

ū in mule

3. A u-shaped mark above the vowel indicates a short sound. medical (mĕd-ĭ-căl)

As in the:

ă in mad

ĕ in bet

ĭ in tip

ŏ in mop

ŭ in cup

4. Primary emphasis is indicated by capital letters. debride (di-BRĒD)

dehydration (dē-hī-DRĀ-shŏn)


Table 1.4 Combining Vowels Tips

Combining Vowel Tip Example
1. Use a combining vowel when connecting a word root to a suffix that begins with a consonant. arthr/o/pathy
2. DO NOT use a combining vowel if the suffix begins with a vowel. hepat/ic
3. Use a combining vowel when connection two word roots, even if vowels are present at the conjunction. oste/o/arthr/itis
4. DO NOT use a combining vowel when connect a prefix and a word root. sub/hepat/ic


Table 1.5 Word Parts and Combining Forms

Part Definition Example
Word Root Core of the word hepat/itis
Suffix Attached to the end of a word root to alter its meaning hepat/itis
Prefix Attached to the beginning of the word root to alter its meaning sub/hepatic
Combining Vowel Typically an “o” used to assist pronunciation hepat/o/magaly
Combining Form Word root with a combining vowel hepat/o


Table 1.6 Medical Terminology Learning Techniques

Analyze 1. Divide into word parts

2. Label the word parts

3. Underline and label each combining form

1. oste/o/arthr/o/pathy

2. oste =WR/ o= CV/ arthr = WR/ o = CV/ pathy = S

3. oste/o/arthr/o/pathy

Define 1. Define each word part in the term

2. Begin defining the suffix meaning and then move to the beginning of the term

1. oste = bone, arthr = joint, pathy= disease

2. Disease of the bone and joint

Build 1. Place word parts together to add terms

2. Add combining vowels

1. Disease of the bone and joint = 

oste/ /arthr/ /pathy

2. oste/o/arthr/o/pathy




Icon for the Creative Commons Attribution 4.0 International License

Medical Terminology Copyright © 2022 by Stacey Grimm; Coleen Allee; Elaine Strachota; Laurie Zielinski; Traci Gotz; Micheal Randolph; and Heidi Belitz is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.

Share This Book