Medical Terminology for Coding Students: A Practical Study Guide
Every code you assign starts with reading the provider's words correctly. Medical terms are built from parts: a prefix at the front, a root or combining form in the middle, and a suffix at the end. If you can split a term into its parts and translate each one, you can usually work out what was wrong with the patient or what was done to them, even when you have never seen the word before. This guide covers the word parts and terms that matter most in coding work. Each section explains the topic in plain language, lists points to memorize, and walks through an example. No code numbers are used; the goal is to build the reading skill that comes before code lookup.
Prefixes: Number, Position, Size, and Color
A prefix sits at the start of a term and changes its meaning. Number prefixes tell you how many: mono- and uni- (one), bi- and di- (two), tri- (three), quadri- and tetra- (four), hemi- and semi- (half), and poly- and multi- (many). In coding, these often signal laterality, how many sites were treated, or how many lesions were removed.
Position prefixes tell you where something is: pre- and ante- (before), post- (after), sub- and infra- (below), supra- and epi- (above or upon), inter- (between), intra- (within), peri- (around), para- (beside), retro- (behind), and trans- (across or through). Hyper- (above normal, excessive) and hypo- (below normal, deficient) also belong on your list because they flip the meaning of a diagnosis.
Size prefixes include macro- and mega- (large) and micro- (small). Color word parts are technically combining forms, but they are usually learned with prefixes: erythr/o (red), leuk/o (white), melan/o (black), cyan/o (blue), xanth/o (yellow), and chlor/o (green).
Key points
- Inter- means between and intra- means within. Intercostal is between the ribs; intravenous is within a vein.
- Hyper- and hypo- are opposites. Hypertension and hypotension are different diagnoses with different codes.
- Hemi- and semi- both mean half. Hemiparesis is weakness on one side of the body.
- Erythr/o is red, leuk/o is white, melan/o is black, and cyan/o is blue.
Worked example
Scenario: The note reads 'periarticular injection, right shoulder.' A student reads it as an injection into the joint. Decoding: peri- means around, articul means joint, and -ar means pertaining to. The injection went into the tissue around the joint, not inside it. An intra-articular injection would be inside the joint space. Injection codes are selected by where the needle actually went, so this one prefix changes which procedure you report.
Suffixes for Conditions: -itis, -osis, -algia, -megaly
Condition suffixes tell you what is wrong with a body part. -itis means inflammation. -osis means an abnormal condition, and sometimes an increase, as in leukocytosis (too many white blood cells). -algia means pain, and -dynia also means pain. -megaly means enlargement.
Related suffixes you will meet often include -emia (blood condition), -pathy (disease), -oma (tumor or mass), -iasis (condition, often from stones or parasites), and -malacia (softening).
These suffixes matter because the classification treats inflammation, abnormal states, pain, and enlargement as different conditions. A symptom such as pain is not the same as a disease such as inflammation. Code only what the provider actually documented.
Key points
- -itis is inflammation; -osis is an abnormal condition. Diverticulosis (pouches present) and diverticulitis (pouches inflamed) are classified differently.
- -algia and -dynia both mean pain and usually describe a symptom, not a confirmed disease.
- -megaly means enlargement. Hepatosplenomegaly is enlargement of both the liver and the spleen.
- -osis does not always mean disease. In leukocytosis, it means an increase.
Worked example
Scenario: A patient reports knee discomfort, and the provider's assessment reads 'arthralgia, right knee.' Decoding: arthr means joint and -algia means pain, so the diagnosis is right knee joint pain. Coding: In the ICD-10-CM index, arthralgia directs you to pain in a joint. You code right knee joint pain, which is a symptom. You do not code arthritis, because the provider did not document inflammation or a definitive joint disease.
Surgical Suffixes: -ectomy, -otomy, -ostomy, -plasty, -pexy, -rrhaphy
Surgical suffixes tell you what the surgeon did. -ectomy means removal (excision). -otomy, also written -tomy, means cutting into (incision). -ostomy, also written -stomy, means creating a new opening. That opening can lead to the body surface, as in a colostomy, or it can join two structures, as in a gastrojejunostomy. -plasty means surgical repair or reshaping. -pexy means surgical fixation or suspension. -rrhaphy means suturing.
Other surgical suffixes worth knowing include -centesis (puncture to withdraw fluid), -tripsy (crushing), -desis (binding or fusion), and -lysis (freeing or breaking down).
Procedure codes are often grouped by the action performed. Mixing up removal, incision, and creating an opening sends you to the wrong part of the procedure code set. Operative notes also often combine actions, and each part of the term has to be accounted for.
Key points
- -ectomy means take out; -otomy means cut into; -ostomy means make an opening.
- Tracheotomy is the incision into the trachea. Tracheostomy is the opening that is created and maintained. They are not interchangeable.
- -plasty means repair or reshape, -pexy means fix in place, and -rrhaphy means sew up. Herniorrhaphy is a suture repair of a hernia.
- Read for extent. Partial and total removals are usually reported differently.
Worked example
Scenario: The operative note title reads 'Sigmoid colectomy with end colostomy.' Decoding: col means colon and -ectomy means removal, so part of the colon (the sigmoid portion) was removed. Colostomy means an opening from the colon to the abdominal surface was created. Coding: The procedure involves both a removal and the creation of a stoma. You must find the procedure description that matches both elements. A colectomy that reconnects the bowel ends (an anastomosis) is a different procedure from one that ends in a colostomy.
Diagnostic Suffixes: -scopy, -graphy, -gram
-scopy means visual examination, usually with a scope (endoscope). -graphy means the process of recording, usually an image. -gram is the record or image that results. -graph is the instrument that records. -metry means measurement.
In everyday terms, a mammography is the procedure and a mammogram is the picture. An echocardiography is the ultrasound exam of the heart, and the echocardiogram is the resulting study. Providers use these words loosely, so check whether a test was performed or only reviewed.
For scope procedures, the combining forms in front of -scopy tell you how far the scope went. Esophagoscopy covers only the esophagus. Esophagogastroduodenoscopy covers the esophagus, stomach, and duodenum. Colonoscopy covers the whole colon. Sigmoidoscopy covers a shorter segment. The documented extent drives code family selection.
Key points
- -scopy means looking with a scope; -graphy means the recording process; -gram means the image or record.
- The organs named before -scopy describe how far the scope traveled.
- Biopsy breaks down as bi/o (life) and -opsy (view). It means removing tissue for examination and is usually reported in addition to, or as part of, the scope procedure.
- A 'reviewed' -gram is not the same as a -graphy procedure performed by that provider.
Worked example
Scenario: The report reads 'EGD with biopsy of gastric antrum.' Decoding: EGD stands for esophagogastroduodenoscopy. Esophag/o is esophagus, gastr/o is stomach, duoden/o is duodenum, and -scopy is visual examination. Gastric antrum is the lower part of the stomach. Coding: First confirm the scope reached the extent named in the title. Then select the procedure description for this type of endoscopy that includes biopsy, rather than a diagnostic-only scope. Check the payer and guideline rules if the exam was incomplete.
Root Words for Organs
The root carries the core meaning, usually a body part. Many organs have two roots, one from Greek and one from Latin. The Greek root tends to appear in diagnoses and procedures, such as nephrectomy. The Latin root tends to appear in plain anatomical adjectives, such as renal artery. Both roots point to the same organ.
Common pairs include nephr and ren (kidney), hyster and uter (uterus), oophor and ovari (ovary), orchi and test (testis), ophthalm and ocul (eye), rhin and nas (nose), pneum/pulmon (lung), and derm and cutane (skin). Single roots to know include cardi (heart), hepat (liver), gastr (stomach), enter (intestine), col (colon), oste (bone), arthr (joint), my (muscle), encephal (brain), neur (nerve), splen (spleen), pancreat (pancreas), and cholecyst (gallbladder).
Key points
- Learn the paired roots: nephr and ren (kidney), hyster and uter (uterus), oophor and ovari (ovary), orchi and test (testis).
- Cyst/o can mean the urinary bladder or any sac. Cholecyst specifically means gallbladder.
- Salping/o can mean the fallopian tube or the eustachian tube. Use context to decide.
- A combining vowel, usually o, links roots to each other and to suffixes that start with a consonant.
Worked example
Scenario: The procedure is listed as 'total abdominal hysterectomy with bilateral salpingo-oophorectomy.' Decoding: hyster means uterus and -ectomy means removal. Salping means fallopian tube and oophor means ovary. Bilateral means both sides. Coding: The uterus, both tubes, and both ovaries were removed through an abdominal incision. You need a procedure description that captures the approach (abdominal), the extent (total), and the removal of the tubes and ovaries. Do not report a hysterectomy alone.
Directional and Positional Terms
Directional terms describe where something is relative to something else. Anterior (also called ventral) means front. Posterior (also called dorsal) means back. Superior (cranial, cephalad) means toward the head, and inferior (caudal) means toward the feet. Medial means toward the midline and lateral means away from it. Proximal means closer to the trunk or point of attachment, and distal means farther away. Superficial means near the surface and deep means farther in. Ipsilateral means the same side, contralateral means the opposite side, and bilateral means both sides.
Hands and feet have their own terms. Palmar (or volar) is the palm side of the hand. Plantar is the sole of the foot. The dorsal surface is the back of the hand and the top of the foot.
Positional terms describe how the patient was placed. Supine is lying face up and prone is lying face down. Lateral decubitus is lying on one side. Lithotomy is lying on the back with hips and knees bent and legs in stirrups. Trendelenburg is lying on the back with the head lower than the feet. Fowler is semi-sitting. Patient position rarely changes a code, but it can help confirm the approach or site.
Key points
- Proximal means closer to the trunk; distal means farther from the trunk. The classification often uses 'upper end' and 'lower end' for long bones.
- Dorsal on the foot is the top, not the sole. The sole is plantar.
- Ipsilateral means same side and contralateral means opposite side. Always confirm laterality before coding.
- Supine is face up and prone is face down.
Worked example
Scenario: The diagnosis reads 'closed fracture, distal radius, left, initial encounter.' Decoding: The radius is the forearm bone on the thumb side. Distal means the end farthest from the elbow, near the wrist. Coding: In ICD-10-CM, look up a fracture of the radius at the lower end. Then specify the left side, closed fracture, and initial encounter, plus any fracture pattern the provider documented. Choosing the upper end or the shaft by mistake would code the wrong site.
Planes and Body Cavities
Planes are imaginary flat surfaces used to divide the body, mainly in imaging reports. The sagittal plane divides the body into left and right parts. The midsagittal plane makes equal halves. The coronal plane, also called frontal, divides the body into front and back. The transverse plane, also called axial or horizontal, divides the body into upper and lower parts. CT scans are usually viewed as axial slices.
The dorsal cavity holds the cranial cavity (brain) and the spinal cavity (spinal cord). The ventral cavity is split by the diaphragm. Above it is the thoracic cavity, which contains the pleural cavities around the lungs and the mediastinum, which holds the heart in its pericardial cavity. Below it is the abdominopelvic cavity. Some organs, such as the kidneys, sit behind the peritoneum and are called retroperitoneal.
The abdomen is described by four quadrants (right upper, left upper, right lower, left lower) or by nine regions. The nine regions are the right and left hypochondriac, epigastric, right and left lumbar, umbilical, right and left iliac (inguinal), and hypogastric (suprapubic).
Key points
- Sagittal divides left and right; coronal (frontal) divides front and back; transverse (axial) divides top and bottom.
- The diaphragm separates the thoracic cavity from the abdominopelvic cavity.
- Laparoscopy enters the abdominal cavity and thoracoscopy enters the chest cavity, so the cavity tells you the approach.
- Know the four quadrants and the nine regions. Several abdominal pain codes are specific to location.
Worked example
Scenario: An emergency department note reads 'RLQ pain, rule out appendicitis; CT abdomen/pelvis negative.' Decoding: RLQ means right lower quadrant, which contains the appendix, cecum, and in females the right ovary and tube. Coding: In the outpatient setting, a diagnosis listed as 'rule out' is not coded as confirmed. Because the CT was negative and no definitive diagnosis was made, you code right lower quadrant abdominal pain. The classification has a location-specific choice for this, so do not default to unspecified abdominal pain.
Common Abbreviations in Operative Notes
Operative notes are full of shorthand. Frequent examples include I&D (incision and drainage), ORIF (open reduction internal fixation), EBL (estimated blood loss), EUA (examination under anesthesia), D&C (dilation and curettage), TURP (transurethral resection of the prostate), PEG (percutaneous endoscopic gastrostomy), LOA (lysis of adhesions), ex lap (exploratory laparotomy), and lap chole (laparoscopic cholecystectomy). Common anesthesia abbreviations are GETA (general endotracheal anesthesia) and MAC (monitored anesthesia care). Other everyday shorthand includes Fx (fracture), Bx (biopsy), Dx (diagnosis), Hx (history), s/p (status post), and PACU (post-anesthesia care unit).
Some abbreviations have more than one meaning. MS can mean multiple sclerosis, mitral stenosis, or morphine sulfate. PE can mean pulmonary embolism or physical exam. When context does not settle the meaning, do not guess. Check the facility's approved abbreviation list or query the provider.
Key points
- ORIF means open reduction internal fixation, which is open treatment with hardware.
- s/p means status post. It usually describes a past event or procedure, not a current condition.
- Abbreviations with more than one meaning (MS, PE, CA) need context or a provider query.
- EBL, PACU, and NPO describe the care process. They rarely drive code selection on their own.
Worked example
Scenario: The note reads 'Pt s/p fall from ladder, Fx L distal radius. ORIF under GETA. EBL 50 mL. To PACU stable.' Decoding: The patient fell from a ladder and fractured the left distal radius. Open reduction with internal fixation was done under general endotracheal anesthesia, with about 50 mL of blood loss, and the patient went to recovery in stable condition. Coding: The procedure is open treatment of a distal radius fracture with internal fixation. The diagnosis is a left distal radius fracture, initial encounter. External cause details, such as a fall from a ladder, can be reported where required. GETA, EBL, and PACU do not change the procedure code.
Pathology Terms
Pathology terms describe the nature of disease. Benign means not cancerous and not spreading. Malignant means cancerous, with the ability to invade and spread. Carcinoma is a malignancy of epithelial tissue, and sarcoma is a malignancy of connective tissue such as bone or muscle. Adenoma is a benign glandular tumor, and adenocarcinoma is a malignant one. In situ means the cancer has not invaded beyond its original layer. Metastasis is spread from the primary (original) site to a secondary site.
Tissue change terms are also important. Hyperplasia is an increase in cell number. Hypertrophy is an increase in cell size. Atrophy is wasting. Dysplasia is abnormal cell development and is often precancerous. Necrosis is tissue death. Ischemia is reduced blood supply, and infarction is tissue death caused by loss of blood supply.
The suffix -oma does not always mean a benign tumor. Melanoma and lymphoma are malignant. Hematoma (a collection of blood) and granuloma (a cluster of inflammatory cells) are not neoplasms at all. For neoplasms, look up the histologic term in the ICD-10-CM Alphabetic Index first, and go to the Neoplasm Table only when directed.
Key points
- 'Metastatic from' points to the primary site. 'Metastatic to' points to the secondary site.
- Carcinoma comes from epithelial tissue; sarcoma comes from connective tissue.
- Not every -oma is benign, and not every -oma is a neoplasm. Look up the term in the Index first.
- Uncertain behavior is a pathologist's determination. It is not the same as 'unspecified,' which means behavior was not documented.
Worked example
Scenario: The pathology report reads 'adenocarcinoma of the sigmoid colon, metastatic to liver.' Decoding: aden means gland and -carcinoma means epithelial malignancy, so this is a malignant glandular tumor. The primary site is the sigmoid colon, and the liver is a secondary (metastatic) site. Coding: Report two conditions, a primary malignant neoplasm of the sigmoid colon and a secondary malignant neoplasm of the liver. Sequencing depends on what the encounter was mainly for, following the official guidelines. Do not code the liver as a primary site.
Combining Forms in Cardiology, GI, Urology, and Neurology
Cardiology: cardi/o (heart), coron/o (coronary vessels), angi/o and vas/o (vessel), arteri/o (artery), phleb/o and ven/o (vein), ather/o (fatty plaque), thromb/o (clot), valvul/o (valve), atri/o (atrium), and ventricul/o (ventricle). GI: esophag/o, gastr/o, duoden/o, jejun/o, ile/o (ileum), col/o, sigmoid/o, proct/o (rectum and anus), hepat/o, chol/e (bile), cholecyst/o (gallbladder), choledoch/o (common bile duct), pancreat/o, and lapar/o (abdominal wall).
Urology: nephr/o and ren/o (kidney), pyel/o (renal pelvis), ureter/o (ureter, which runs from the kidney to the bladder), cyst/o and vesic/o (bladder), urethr/o (urethra, which runs from the bladder to the outside), lith/o (stone), and prostat/o. Neurology: neur/o (nerve), encephal/o (brain), cerebr/o (cerebrum), cerebell/o (cerebellum), mening/o (meninges), myel/o (spinal cord, and also bone marrow), radicul/o (nerve root), and crani/o (skull). Neurology suffixes include -plegia (paralysis), -paresis (partial paralysis or weakness), and -phasia (speech).
Several look-alike forms cause errors. Ile/o is the ileum (small intestine), but ili/o is the ilium (hip bone). Vas/o can mean any vessel or the vas deferens. Myel/o has two meanings. Ureter and urethra are different tubes.
Key points
- Cardiology: ather/o means plaque, thromb/o means clot, and angi/o means vessel. Atherosclerosis and thrombosis are different conditions.
- GI: cholecyst/o is the gallbladder and choledoch/o is the common bile duct. Ile/o (ileum) is not ili/o (ilium).
- Urology: pyel/o is the renal pelvis. The ureter connects kidney to bladder, and the urethra drains the bladder to the outside.
- Neurology: myel/o can mean spinal cord or bone marrow, and radicul/o means nerve root. Radiculopathy is nerve root disease.
Worked example
Scenario: The discharge diagnosis reads 'acute cholecystitis with choledocholithiasis.' Decoding: cholecyst means gallbladder and -itis means inflammation. Choledoch means common bile duct, lith means stone, and -iasis means condition. So the patient has acute gallbladder inflammation plus stones in the common bile duct. Coding: ICD-10-CM provides combination codes for bile duct calculus with cholecystitis, specifying acute or chronic and whether there is obstruction. When the classification has a combination code that captures both conditions, use it instead of coding each separately.
Common mistakes
- Confusing -ectomy, -otomy, and -ostomy. Removing, cutting into, and creating an opening are different procedures.
- Treating tracheotomy and tracheostomy as the same word.
- Mixing up look-alike terms: ureter and urethra, ileum and ilium, and perineal, peroneal, and peritoneal.
- Coding -itis when the provider documented -osis, or the reverse. Diverticulosis is not diverticulitis.
- Coding a symptom such as -algia as if it were a disease, or coding a symptom in addition to a confirmed diagnosis that routinely explains it.
- Assuming every -oma is benign. Melanoma and lymphoma are malignant, and hematoma is not a neoplasm.
- Reversing primary and secondary sites when reading 'metastatic from' and 'metastatic to.'
- Reading s/p (status post) as a current condition instead of a past event or procedure.
- Guessing the meaning of an abbreviation that has more than one meaning instead of checking context or querying the provider.
- Laterality and direction errors, such as reading dorsal foot as the sole or confusing proximal and distal.
- Confusing hyper- and hypo-, or inter- and intra-. These prefixes reverse or relocate the meaning of a term.
- Treating -gram and -graphy as the same thing, or not checking the documented extent of a -scopy procedure.
- Forgetting that myel/o can mean spinal cord or bone marrow, and that salping/o can mean the fallopian tube or the eustachian tube.
- Splitting a compound term into separate codes when the classification offers a single combination code.
Written with AI and checked automatically (2026-10-14). See our editorial policy.