A prefix changes the meaning of a word root by adding detail about how, when, where, or how much. You’ll see prefixes in almost every medical field: from anatomy to diagnostics.

Directional Prefixes

These prefixes help describe where something is located or how it's moving in the body.

Inter- = between
- Intervertebral – between the vertebrae of the spine
Intra- = within
- Intramuscular – within a muscle
Para- = near or beside
- Paraspinal – near the spine
Circum- = around
- Circumoral – around the mouth
Exo- = outside
- Exocrine – glands that secrete outward (e.g., sweat glands)
Endo- = inside
- Endoscope – an instrument used to view inside the body

Time-Related Prefixes

These indicate when something happens in relation to a procedure or event.

Re- = again
- Reinfection – becoming infected again
Peri- = around
- Perinatal – the time around birth
Post- = after
- Postoperative – after surgery
Co- / Con- = with, together
- Congenital – a condition present from birth

Quantity and Number Prefixes

These prefixes deal with amounts or measurements in the body.

Hemi- = half

Hemiplegia – paralysis on one side of the body

Multi- = many

Multigravida – a woman who has been pregnant multiple times

Micro- = small

Microcephaly – abnormally small head size

Macro- = large

Macrophage – a large cell that eats foreign particles

Nulli- = none

Nullipara – a woman who has never given birth

Understanding prefixes gives you context. For example, knowing that “intra-” means “within” helps you figure out that “intracranial” refers to something inside the skull.

A suffix completes the word by telling you what’s happening—whether it’s a condition, a process, or the specialty involved. Let’s look at how suffixes are categorized and used.

Diagnostic and Procedural Suffixes

These suffixes relate to testing, examining, or treating the body.

-centesis = surgical puncture to remove fluid
- Amniocentesis – removing fluid from the amniotic sac during pregnancy
-desis = binding or surgical fusion
- Arthrodesis – surgical fusion of a joint
-lysis = breakdown or destruction
- Dialysis – removing waste from the blood (breaking it down)
-pexy = surgical fixation
- Nephropexy – fixing a kidney in place
-tome = instrument used to cut
- Osteotome – a surgical instrument used to cut bone

Conditions and Symptoms

These suffixes describe medical issues, whether they’re chronic, acute, or developmental.

-cele = hernia or protrusion
- Meningocele – a hernia of the meninges (the covering of the brain and spinal cord)
-phagia = eating or swallowing
- Dysphagia – difficulty swallowing
-phasia = speech
- Aphasia – inability to speak
-spasm = involuntary contraction
- Bronchospasm – involuntary tightening of the airway muscles
-rrhexis = rupture
- Cardiorrhexis – rupture of the heart wall
-stenosis = narrowing
- Tracheostenosis – narrowing of the trachea (windpipe)

Specialties and Professions

Some suffixes tell you who studies or treats a condition or what they study.

-iatry = medical treatment or specialty

Podiatry – medical care of the feet

-ist = one who practices

Pharmacist – someone who prepares and dispenses medications

-logist = specialist in a field

Endocrinologist – a doctor who specializes in hormone-related conditions

-logy = study of

Pathology – the study of disease

Understanding suffixes helps you spot the difference between terms. For example, “neurologist” is the specialist, and “neurology” is the field of study. Small endings, big differences.

Illustrations representing gynecology, dermatology, and urology specialties. — inspiring.team / Shutterstock

Most medical terms use a prefix + root + suffix structure. Here's an example built using parts from this lesson (and not repeated from previous lessons):

Prefix: Inter- (between)
Root: cost (rib)
Suffix: -al (pertaining to)
Term: Intercostal – Pertaining to between the ribs

Another example:

Prefix: Dys- (abnormal)
Root: phagia (eating)
Term: Dysphagia – Difficulty or abnormal eating/swallowing

Diagram showing how word roots and suffixes form medical terms like cardiology, cardiologist, and cardiopathy.

Diagram showing prefix, root, and suffix forming the word 'pericarditis' with its meaning.

Being able to break terms apart this way helps you decode long or unfamiliar words with ease.

In a fast-paced healthcare setting, there’s no time for confusion. One wrong interpretation of a word could lead to a serious mistake. That’s why understanding both prefixes and suffixes is critical:

Improves clarity in medical records and instructions
Reduces errors in communication with patients and providers
Enhances understanding of symptoms, conditions, and treatments
Supports your career if you plan to work in healthcare

Whether you’re reading a lab report or explaining a condition to a patient, being able to define and use medical terms accurately makes a big difference.

Sometimes, one condition may be described in more than one way:

Otalgia = pain in the ear
Ear pain = plain English version of the same concept

Both phrases mean the same thing, but “otalgia” is used in medical records, while “ear pain” is easier for patients to understand. Being able to recognize both forms of a term is a key part of medical communication.

Unit 1 Using Prefixes and Suffixes to Shape Meaning

Instructions

Conclusion: Learning the Medical Lexicon

Instructions

Prefixes: Direction, Time, and Quantity

Directional Prefixes

Time-Related Prefixes

Quantity and Number Prefixes

Suffixes: Conditions, Procedures, and Specialties

Diagnostic and Procedural Suffixes

Conditions and Symptoms

Specialties and Professions

Combining Prefixes and Suffixes

Why It’s Important to Know the Parts

When Words Mean the Same Thing

Conclusion: Learning the Medical Lexicon