Medical Terminology for Healthcare Workers

Medical terminology is the shared language of healthcare. Every clinical note, verbal handoff, care plan, and physician order uses standardized terms built from Greek and Latin word parts. When a nurse reports that a patient has "bilateral pedal edema" or that someone is "NPO post-op," you need to understand exactly what that means to provide safe, effective care. Misunderstanding even a single term can lead to errors in patient care.

This guide teaches you how medical terms are constructed, the most important prefixes, suffixes, and root words organized by body system, common abbreviations you will encounter daily, and how to apply this knowledge in real clinical settings.

How Medical Terms Are Built

The vast majority of medical terms are assembled from three types of word parts. Once you learn approximately 100 word parts, you can decode thousands of terms you have never seen before.

Prefixes

A prefix appears at the beginning of a word and modifies its meaning. Prefixes often describe quantity, location, time, or status.

Root Words

The root is the core of the term and typically refers to a body part or organ. Most medical terms have at least one root word. Some have two (for example, "gastroenteritis" has gastro- for stomach and enter- for intestine).

A combining vowel (usually "o") is often inserted between roots or between a root and a suffix to make the word easier to pronounce. The combining form is the root plus its vowel: cardi/o, gastr/o, oste/o.

Suffixes

A suffix appears at the end of a word and usually indicates a condition, disease, procedure, or descriptive quality.

Example: Electrocardiography

• Electr/o (root) = electrical
• Cardi/o (root) = heart
• -graphy (suffix) = process of recording
• Meaning: the process of recording the electrical activity of the heart

Example: Subcutaneous

• Sub- (prefix) = below, under
• Cutane (root) = skin
• -ous (suffix) = pertaining to
• Meaning: pertaining to below the skin (as in a subcutaneous injection)

Essential Prefixes

Prefixes of Quantity and Size

Prefix	Meaning	Clinical Example
uni-	one	unilateral (one side)
bi-	two, both	bilateral (both sides)
tri-	three	tricuspid (three-cusped valve)
quad-	four	quadriplegia (paralysis of all four limbs)
hemi-	half	hemiplegia (paralysis of one side of the body)
poly-	many	polyuria (excessive urination)
oligo-	few, scanty	oliguria (decreased urine output)
micro-	small	microscopic (too small to see with the naked eye)
macro-	large	macrocephaly (abnormally large head)
multi-	many	multifocal (occurring in many locations)

Prefixes of Location and Direction

Prefix	Meaning	Clinical Example
sub-	below, under	sublingual (under the tongue)
supra-	above	suprapubic (above the pubic bone)
epi-	upon, above	epidermis (outer layer of skin)
endo-	within	endoscopy (looking within a body cavity)
peri-	around	pericardium (membrane around the heart)
inter-	between	intercostal (between the ribs)
intra-	within	intravenous (within a vein)
retro-	behind, backward	retroperitoneal (behind the peritoneum)
trans-	across, through	transdermal (through the skin)
ante-	before, in front	antecubital (in front of the elbow)

Prefixes of Status and Condition

Prefix	Meaning	Clinical Example
hyper-	above normal, excessive	hypertension (high blood pressure)
hypo-	below normal, deficient	hypoglycemia (low blood sugar)
tachy-	fast	tachycardia (heart rate above 100 bpm)
brady-	slow	bradycardia (heart rate below 60 bpm)
a- / an-	without, absence of	apnea (absence of breathing)
dys-	difficult, painful, abnormal	dysphagia (difficulty swallowing)
anti-	against	anticoagulant (against clotting)
pre-	before	preoperative (before surgery)
post-	after	postpartum (after childbirth)
neo-	new	neoplasm (new, abnormal growth / tumor)
pseudo-	false	pseudoseizure (not a true seizure)
pan-	all	pandemic (affecting all people across regions)

Essential Suffixes

Suffixes Indicating Conditions

Suffix	Meaning	Clinical Example
-itis	inflammation	appendicitis (inflammation of the appendix)
-osis	abnormal condition	cyanosis (bluish discoloration from low oxygen)
-emia	blood condition	septicemia (bacteria in the blood / sepsis)
-algia	pain	neuralgia (nerve pain)
-penia	deficiency	thrombocytopenia (low platelet count)
-megaly	enlargement	hepatomegaly (enlarged liver)
-malacia	softening	osteomalacia (softening of the bones)
-sclerosis	hardening	atherosclerosis (hardening of the arteries)
-stenosis	narrowing	spinal stenosis (narrowing of the spinal canal)
-oma	tumor, mass	carcinoma (malignant tumor)
-pathy	disease	neuropathy (disease of the nerves)
-plegia	paralysis	paraplegia (paralysis of the lower body)

Suffixes Indicating Procedures

Suffix	Meaning	Clinical Example
-ectomy	surgical removal	cholecystectomy (removal of the gallbladder)
-otomy	cutting into	tracheotomy (cutting into the trachea)
-ostomy	creating an opening	colostomy (creating an opening in the colon)
-plasty	surgical repair	arthroplasty (joint replacement surgery)
-scopy	visual examination	colonoscopy (visual exam of the colon)
-graphy	process of recording	radiography (process of taking X-rays)
-centesis	surgical puncture to remove fluid	thoracentesis (draining fluid from the chest)
-tripsy	crushing	lithotripsy (crushing kidney stones)

Suffixes That Describe

Suffix	Meaning	Clinical Example
-ic, -al, -ous	pertaining to	cardiac (pertaining to the heart)
-logy	study of	pathology (study of disease)
-logist	one who studies	cardiologist (heart specialist)
-pnea	breathing	dyspnea (difficult breathing)
-uria	urine condition	hematuria (blood in urine)
-rrhea	flow, discharge	diarrhea (excessive flow from bowels)
-rrhage	bursting forth	hemorrhage (bursting forth of blood)
-phasia	speech	aphasia (loss of speech ability)
-phagia	eating, swallowing	dysphagia (difficulty swallowing)

Body System Terminology

Cardiovascular System

Root/Combining Form	Meaning	Key Terms
cardi/o	heart	cardiomyopathy, cardiac arrest, tachycardia
angi/o, vas/o	vessel	angioplasty, vascular, vasoconstriction
arter/o	artery	arteriosclerosis, arterial blood gas (ABG)
ven/o, phleb/o	vein	venous, phlebotomy, deep vein thrombosis
hem/o, hemat/o	blood	hemorrhage, hematoma, hematocrit
thromb/o	clot	thrombosis, thrombolytic, thrombocytopenia

Clinical vital sign ranges:

• Normal adult heart rate: 60 to 100 beats per minute
• Normal adult blood pressure: less than 120/80 mmHg
• Hypertension Stage 1: 130-139/80-89 mmHg
• Hypertension Stage 2: 140+/90+ mmHg
• Hypertensive crisis: above 180/120 mmHg

Respiratory System

Root/Combining Form	Meaning	Key Terms
pulmon/o, pneum/o	lung	pulmonary embolism, pneumonia, pneumothorax
bronch/o	bronchus	bronchitis, bronchodilator, bronchoscopy
thorac/o	chest	thoracentesis, thoracotomy
ox/o	oxygen	hypoxia, pulse oximetry, hypoxemia
laryng/o	larynx	laryngitis, laryngoscope
trache/o	trachea	tracheostomy, endotracheal tube

Clinical vital sign ranges:

• Normal adult respiratory rate: 12 to 20 breaths per minute
• Normal oxygen saturation (SpO2): 95% to 100%
• Tachypnea: respiratory rate above 20
• Bradypnea: respiratory rate below 12

Musculoskeletal System

Root/Combining Form	Meaning	Key Terms
oste/o	bone	osteoporosis, osteomyelitis
arthr/o	joint	arthritis, arthroscopy, arthroplasty
my/o, myos/o	muscle	myalgia, myocardial, myositis
chondr/o	cartilage	chondromalacia, costochondritis
tend/o, tendin/o	tendon	tendonitis, tendon repair
cost/o	rib	intercostal, costochondritis

Gastrointestinal System

Root/Combining Form	Meaning	Key Terms
gastr/o	stomach	gastritis, gastroenterology
enter/o	intestine	gastroenteritis, enteral nutrition
hepat/o	liver	hepatitis, hepatomegaly
col/o, colon/o	colon	colitis, colostomy, colonoscopy
cholecyst/o	gallbladder	cholecystitis, cholecystectomy
pancreat/o	pancreas	pancreatitis

Nervous System

Root/Combining Form	Meaning	Key Terms
neur/o	nerve	neuropathy, neuralgia, neurology
cerebr/o, encephal/o	brain	cerebrovascular, encephalitis
mening/o	meninges	meningitis
psych/o	mind	psychosis, psychotropic

Urinary System

Root/Combining Form	Meaning	Key Terms
ren/o, nephr/o	kidney	renal failure, nephrology, nephritis
cyst/o	bladder	cystitis, cystoscopy
ur/o	urine	urinalysis, urinary retention
lith/o	stone	nephrolithiasis (kidney stones), lithotripsy

Integumentary System (Skin)

Root/Combining Form	Meaning	Key Terms
derm/o, dermat/o	skin	dermatitis, dermatology, subcutaneous
cutane/o	skin	subcutaneous, percutaneous

Common Medical Abbreviations

These abbreviations appear constantly in care plans, nursing notes, physician orders, and shift handoffs. Memorize them.

Vital Signs and Assessment

• BP - Blood pressure
• HR - Heart rate (pulse)
• RR - Respiratory rate
• T or Temp - Temperature
• SpO2 or O2 sat - Oxygen saturation
• BMI - Body mass index
• I&O - Intake and output (fluid balance)
• LOC - Level of consciousness
• GCS - Glasgow Coma Scale
• ROM - Range of motion
• WNL - Within normal limits
• VSS - Vital signs stable
• A&O x 3 or A&O x 4 - Alert and oriented to person, place, time (and situation)

Diagnoses and Conditions

• MI - Myocardial infarction (heart attack)
• CVA - Cerebrovascular accident (stroke)
• CHF - Congestive heart failure
• COPD - Chronic obstructive pulmonary disease
• DM - Diabetes mellitus
• HTN - Hypertension (high blood pressure)
• UTI - Urinary tract infection
• DVT - Deep vein thrombosis
• PE - Pulmonary embolism
• GERD - Gastroesophageal reflux disease
• CAD - Coronary artery disease
• TIA - Transient ischemic attack (mini-stroke)
• SOB - Shortness of breath
• Fx - Fracture
• Hx - History
• Dx - Diagnosis
• Tx - Treatment
• Rx - Prescription
• Sx - Symptoms
• Bx - Biopsy

Medication Administration

• PO - By mouth (per os)
• IV - Intravenous
• IM - Intramuscular
• SQ or SubQ - Subcutaneous
• PR - Per rectum
• SL - Sublingual (under the tongue)
• NPO - Nothing by mouth (nil per os)
• PRN - As needed (pro re nata)
• BID - Twice a day
• TID - Three times a day
• QID - Four times a day
• QD - Once daily (Note: many facilities have placed this on the "Do Not Use" list due to confusion with QID)
• Q4H, Q6H, Q8H - Every 4, 6, or 8 hours
• HS - At bedtime (hour of sleep)
• AC - Before meals (ante cibum)
• PC - After meals (post cibum)
• STAT - Immediately

Documentation and Orders

• ADL - Activities of daily living
• DNR - Do not resuscitate
• DNI - Do not intubate
• POLST - Physician Orders for Life-Sustaining Treatment
• DC or D/C - Discharge or discontinue (context matters)
• w/o - Without
• c (with a line over it) - With
• s (with a line over it) - Without
• R/O - Rule out
• H&P - History and physical
• PT - Physical therapy (or patient, depending on context)
• OT - Occupational therapy
• BMP - Basic metabolic panel (blood test)
• CBC - Complete blood count
• CMP - Comprehensive metabolic panel
• ABG - Arterial blood gas
• UA - Urinalysis

The Joint Commission "Do Not Use" List

The Joint Commission requires that certain abbreviations NOT be used because they have been linked to medication errors:

• U (for units) - Write "units" instead
• IU (for international units) - Write "international units" instead
• QD and QOD - Write "daily" and "every other day" instead
• Trailing zero (X.0 mg) - Write "X mg" instead (the decimal point can be missed)
• Lack of leading zero (.X mg) - Write "0.X mg" instead

Always follow your facility's approved abbreviation list.

Vital Signs: Clinical Terminology and Normal Ranges

Understanding the clinical terminology for vital sign findings is essential for accurate reporting:

Blood Pressure

• Normotensive - Normal blood pressure (less than 120/80)
• Hypertensive - High blood pressure (140/90 or above, or on medication)
• Hypotensive - Low blood pressure (below 90/60)
• Orthostatic hypotension - Blood pressure drop of 20 mmHg systolic or 10 mmHg diastolic within 3 minutes of standing

Heart Rate

• Normal sinus rhythm - Regular rate between 60 and 100 bpm
• Tachycardic - Heart rate above 100 bpm
• Bradycardic - Heart rate below 60 bpm
• Irregular - Uneven spacing between beats (may indicate atrial fibrillation or other arrhythmia)

Temperature

• Afebrile - Without fever (normal: 97.8 to 99.1 degrees F oral)
• Febrile - Having a fever (100.4 degrees F / 38.0 degrees C or higher)
• Hypothermic - Body temperature below 95 degrees F / 35 degrees C
• Hyperthermia - Dangerously elevated body temperature

Respiratory

• Eupnea - Normal breathing
• Tachypnea - Rapid breathing (above 20 breaths per minute)
• Bradypnea - Slow breathing (below 12 breaths per minute)
• Apnea - Absence of breathing
• Dyspnea - Difficulty breathing
• Orthopnea - Difficulty breathing when lying flat

Putting It All Together: Clinical Scenarios

Scenario 1: Shift Report

"Mrs. Johnson is a 72-year-old female, post-op day 2 from a right total hip arthroplasty. She is A&O x 4, VSS. BP 128/76, HR 78, RR 16, SpO2 97% on room air. She has been ambulating TID with PT. Pain is 3/10, managed with acetaminophen PO Q6H PRN. She is on DVT prophylaxis with SubQ heparin BID. Surgical site is clean, dry, and intact with no signs of infection. I&O is balanced. Diet is regular, tolerating well."

Translation: Mrs. Johnson is an alert, fully oriented patient who had her right hip joint replaced two days ago. Her vital signs are stable and within normal ranges. She walks three times daily with physical therapy. Her pain is mild, controlled with oral Tylenol every 6 hours as needed. She receives blood thinner injections twice daily to prevent blood clots. Her surgical wound looks good, and her fluid intake and output are balanced.

Scenario 2: Phone Report to a Physician

"I am calling about Mr. Davis in room 412. He is a 65-year-old male with a Hx of CHF and DM type 2. He is reporting increased SOB and bilateral pedal edema. Current vitals: BP 168/98, HR 110, RR 28, SpO2 89% on 2L NC. I&O for the past 24 hours shows a positive fluid balance of 1500 mL. His BNP came back elevated at 1200. I suspect CHF exacerbation."

Translation: A patient with a history of heart failure and diabetes is having increased shortness of breath and swelling in both feet. His blood pressure and heart rate are elevated, he is breathing fast, and his oxygen level is low. He has taken in much more fluid than he has put out, and a blood test indicates his heart failure is worsening.

Tips for Learning Medical Terminology

1. Break every new word into parts - Identify the prefix, root(s), and suffix, then translate each piece. With practice this becomes automatic.
2. Learn word parts, not whole words - Memorizing 100 word parts unlocks thousands of terms. Memorizing individual terms is inefficient.
3. Use flashcards for abbreviations - You will encounter abbreviations every shift. Physical or digital flashcards with daily review work well.
4. Practice in context - Read nursing notes and physician orders and translate each term. Real clinical documentation is the best study material.
5. Ask when you do not understand - Never pretend to understand a term during a patient handoff or when receiving orders. Patient safety depends on clear communication. Write down the term, ask for clarification, and look it up later.
6. Learn your facility's approved abbreviation list - Every facility has a list of approved abbreviations and a separate list of prohibited abbreviations. Familiarize yourself on day one.
7. Pay attention to look-alike and sound-alike terms - Ileum (part of the small intestine) vs. ilium (hip bone). Hyper- (above normal) vs. hypo- (below normal). These distinctions matter.