Medical Terminology for PSWs — Prefixes, Suffixes & Root Words

Medical terminology can feel overwhelming when you first encounter it. Words like "tachycardia," "dysphagia," and "hemiplegia" look like they belong in a medical school textbook, not a PSW program. But here is the good news: almost every medical term is built from a small number of reusable parts. Once you learn the building blocks — prefixes, root words, and suffixes — you can decode nearly any medical term you encounter, even ones you have never seen before.

This guide covers the medical terminology you will read in daily practice as a PSW and while preparing for the NACC certification exam. We will break down how medical terms are constructed, give you the most important prefixes, suffixes, and root words to memorize, and cover the abbreviations you will see in care plans, medication administration records, and clinical documentation every single day.

Short answer: Many medical terms are built from recognizable parts — often a prefix, a root word and a suffix — so learning the parts lets you decode most unfamiliar terms; the rest you look up. PSWs also read timing and route abbreviations on a medication administration record (MAR) or care plan, and ISMP Canada's Do Not Use list names abbreviations that must never be used in medication information.

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How are medical terms built?

Many medical terms are built from up to three parts: a prefix at the front, a root word in the middle and a suffix at the end. To define a term, start with the suffix, then read the prefix and root. Terms that are not built from Greek and Latin word parts have to be learned on their own. The pattern looks like this:

Prefix + Root Word + Suffix = Medical Term

• Prefix: Comes at the beginning and modifies the meaning (e.g., hypo- = below normal)
• Root word: The core of the term, usually referring to a body part or system (e.g., glyc = sugar)
• Suffix: Comes at the end and usually indicates a condition, procedure, or status (e.g., -emia = blood condition)

Example: Hypo + glyc + emia = Hypoglycemia (low blood sugar)

Not every medical term has all three parts. Some have just a root and suffix (carditis = inflammation of the heart), and some have a prefix and root without a distinct suffix (hypertension = high blood pressure). But the formula works for the vast majority of terms you will encounter.

A combining vowel (usually "o") is often added between the root word and the suffix to make the term easier to pronounce. That is why you see "cardi/o" rather than just "cardi" — the "o" connects the root to the next part of the word. The combining vowel is typically dropped when the suffix begins with a vowel (e.g., card + itis = carditis, not cardioitis).

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Which prefixes do PSWs need to know?

A prefix sits at the front of a medical term and changes the meaning of the root word. These 20 prefixes — for example hypo-, hyper-, tachy-, brady- and dys- — are a good place to start, and you will meet them in care plans, chart notes and shift reports:

Which prefixes should you learn together?

Two opposite pairs and two further prefixes are worth learning together, because they describe conditions that a PSW observes and reports on in daily practice:

• Hypo- vs. Hyper-: Low vs. high. You must know these for blood pressure (hypotension/hypertension), blood sugar (hypoglycemia/hyperglycemia), and body temperature (hypothermia/hyperthermia).
• Tachy- vs. Brady-: Fast vs. slow. These apply primarily to heart rate (tachycardia/bradycardia) and breathing rate (tachypnea/bradypnea).
• Dys-: Difficult or abnormal. Dyspnea (difficulty breathing), dysphagia (difficulty swallowing), and dysuria (painful urination) all describe something that is difficult, painful or not working normally.
• A- / An-: Without. Apnea (without breathing), anemia (deficiency of red blood cells), and anuria (no urine output) all describe something that is absent or lacking.

Practice example. Decode the term before you look at the answer.

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Which suffixes do PSWs need to know?

Suffixes come at the end of a medical term and usually indicate a condition, disease, procedure, or status. These 15 suffixes turn up in PSW documentation:

Suffixes You Must Not Confuse

Some suffixes look and sound alike but describe very different things. These are the pairs worth slowing down on:

• -ectomy (removal) vs. -ostomy (creating an opening) vs. -otomy (cutting into): A colectomy removes part of the colon. A colostomy creates a new opening from the colon to the abdominal surface. A colotomy cuts into the colon.
• -pnea (breathing) vs. -phagia (swallowing): Dyspnea is difficulty breathing. Dysphagia is difficulty swallowing. These two terms sound similar but describe very different conditions.
• -itis (inflammation) vs. -osis (condition): Arthritis is inflammation of the joints. Arthrosis is a degenerative joint condition. The suffix changes the meaning significantly.

Practice example. Break the term into its two parts, then choose.

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Which root words are useful in PSW care?

Root words identify the body part or system a term refers to — for example cardi/o (heart), pulmon/o (lungs), neur/o (nerves) and derm/o (skin). Pair one of these roots with a prefix or a suffix and a great deal of what is written in a care plan becomes readable:

Putting It All Together

Once you know the building blocks, you can decode terms systematically. Here are some examples:

• Gastroenteritis: gastr/o (stomach) + enter/o (intestines) + -itis (inflammation) = inflammation of the stomach and intestines
• Bradycardia: brady- (slow) + cardi/o (heart) + -a = slow heart rate
• Hemiplegia: hemi- (half) + -plegia (paralysis) = paralysis of one half of the body
• Osteoporosis: oste/o (bone) + -porosis (porous condition) = porous, weakened bones
• Nephritis: nephr/o (kidney) + -itis (inflammation) = inflammation of the kidney

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Which abbreviations do PSWs use in care settings?

As a PSW you will read abbreviations in care plans, medication records and messages from nurses every day. The tables below group them by where you meet them — medication and timing, clinical documentation, and positioning:

Medication and Timing Abbreviations

Clinical and Documentation Abbreviations

Positioning and Care Abbreviations

Practice example. Read the care-plan line the way you would on shift.

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Which abbreviations should a PSW never use in medication documentation?

ISMP Canada's Do Not Use list names abbreviations, symbols and dose designations that must not be used when medication information is communicated. That governs what you write; it also tells you which forms to treat as unsafe when you see them on a medication administration record or care plan. If you see one of these on a chart, do not act on your own reading of it.

Recognizing one of these abbreviations is not authorization to act on it. A PSW reads medication information; deciding what a medication instruction means for a client is a clinical decision. If an instruction is unclear or ambiguous, or if it uses one of the forms above, take it to the nurse or the most accountable person before anything is given, and record the direction you are given.

Follow your employer's documentation policy for what you may write, and ask when you are not sure whether an abbreviation is approved where you work. An abbreviation being absent from the list above is not the same as your employer approving it. For the line between reading a medication instruction and acting on one, see what a PSW may and may not do with medications.

Source: ISMP Canada's 2025 Do Not Use list and the May 29, 2025 bulletin, accessed September 18, 2026 (see Sources).

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How to practise medical terminology for the NACC exam

Practice questions are a quick way to find the terms you cannot yet decode. A practice question can use medical terminology in four ways, and each one trains a different skill:

1. Direct definition questions: You are asked what a specific term means (for example, what dysphagia means). These are straightforward once you know your prefixes and suffixes.

2. Scenario questions that use medical terms: A scenario describes a client with dyspnea or hematuria and asks what you would do. You have to decode the term before you can read the situation.

3. Abbreviation interpretation: A question quotes a care-plan excerpt and asks what its abbreviations mean.

4. Documentation questions: A question asks which term or abbreviation belongs in a written record of what you observed.

You do not need the vocabulary of a physician or a nurse. Aim at the terms and abbreviations that are directly relevant to PSW practice, and start with the building blocks in this guide.

Practice example. Decide what the term tells you, and what it does not.

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How do you memorize medical terminology?

Memorize the building blocks rather than the finished terms: a few dozen prefixes, roots and suffixes go a long way. Then reinforce them with flashcards, body-system grouping, real care plans and saying the terms out loud. These six habits are what make the memorization stick.

1. Learn the Building Blocks First, Not Individual Terms

Do not try to memorize hundreds of medical terms as isolated vocabulary words. Instead, memorize the prefixes, suffixes, and root words in this guide. Once you know that "tachy-" means fast and "-cardia" refers to the heart, you will never forget what tachycardia means — and you will also be able to decode tachypnea (fast breathing) without having memorized it separately.

2. Use Flashcards with the Three-Part Breakdown

Create flashcards where one side has the medical term and the other side breaks it into prefix + root + suffix with the meaning of each part. This reinforces the pattern-recognition skill rather than rote memorization.

3. Group Terms by Body System

Study related terms together. When you study the cardiovascular system, learn tachycardia, bradycardia, hypertension, hypotension, myocardial, and cardiology all at once. The shared roots and patterns reinforce each other.

4. Practise with Care Plans

Ask your clinical supervisor if you can review care plans (with proper authorization) and decode the medical terms and abbreviations you find. Real-world context makes the terms stick much better than flashcards alone.

5. Say the Words Out Loud

Medical terminology is easier to remember when you have heard it and said it. Practise pronouncing the terms as you study. Many students skip this step and then freeze on placement when they hear a term spoken for the first time.

6. Connect Terms to Your Clinical Experiences

Every time you encounter a medical term in placement — on a chart, in a care plan, or spoken by a nurse — write it down and look it up. Terms you encounter in real clinical situations are the ones you will remember on exam day.

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Which 10 terms should every PSW know?

These ten terms cover breathing, swallowing, heart rate, blood pressure, blood sugar, mobility and skin colour — the things a PSW observes and reports on every shift. If you memorize nothing else, memorize these:

1. Dyspnea — difficulty breathing
2. Dysphagia — difficulty swallowing
3. Tachycardia — rapid heart rate
4. Bradycardia — slow heart rate
5. Hypertension — high blood pressure
6. Hypotension — low blood pressure
7. Hypoglycemia — low blood sugar
8. Hyperglycemia — high blood sugar
9. Hemiplegia — paralysis of one side of the body
10. Cyanosis — bluish discolouration of the skin (indicates low oxygen)

For each of these terms, know the definition, why it matters for the client, and what you are expected to do when you observe it. What counts as fast or slow for a particular client, and what has to be reported, comes from that client's care plan and your employer's reporting instructions — not from a number in a study guide. Report your observation through your employer's reporting path; if the client is in distress or deteriorating, follow your employer's emergency protocol, which includes calling emergency services when the situation calls for it, rather than holding the observation for a routine report.

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Connecting Terminology to Your Broader Studies

Medical terminology is not a standalone topic — it connects to everything else in your PSW program:

• Vital Signs: Terms like tachycardia, bradycardia, hypertension, and hypotension are directly tied to vital sign measurement and reporting.
• IPAC and Infection Control: Terms like "-itis" (inflammation, often caused by infection) and "sepsis" connect to your infection control knowledge.
• Scope of Practice: Understanding medical terminology helps you interpret care plans accurately, which is essential for staying within your scope.
• How to Pass the NACC Exam: Terminology rewards steady, repeatable study — that guide sets out how to build the study plan around it.

The investment you make in learning these building blocks now will pay dividends throughout your career. Every care plan you read, every shift report you hear, and every conversation with a nurse will make more sense when you understand the language of health care.

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Sources

• ISMP Canada, Do Not Use: List of Dangerous Abbreviations, Symbols, and Dose Designations — resource page (accessed September 18, 2026).
• ISMP Canada, Do Not Use: Dangerous Abbreviations, Symbols, and Dose Designations, 2025 edition — the detailed list quoted in the table above, PDF (accessed September 18, 2026).
• ISMP Canada, Do Not Use: Dangerous Abbreviations, Symbols, and Dose Designations — 2025 Update — bulletin published May 29, 2025 (accessed September 18, 2026).
• Ernstmeyer K, Christman E, editors. Medical Terminology, 2nd edition, Chapter 1, Foundational Concepts – Identifying Word Parts. Eau Claire (WI): Chippewa Valley Technical College; 2024 (accessed September 18, 2026).

Frequently Asked Questions

What medical terms should PSWs know?

PSWs should know common prefixes (hypo-, hyper-, tachy-, brady-), suffixes (-itis, -ectomy, -osis, -emia), root words (cardi/o, pulmon/o, neuro), and abbreviations used in care settings (ADL, PRN, NPO, BID, TID, QID, SOB, VS). Understanding these building blocks lets you decode most medical terms you will encounter in documentation and care plans.

What does 'hypo' mean in medical terms?

The prefix 'hypo-' means below normal, under, or deficient. For example, hypotension means low blood pressure, hypothermia means low body temperature, and hypoglycemia means low blood sugar. The opposite prefix is 'hyper-', which means above normal or excessive.

What does PRN mean?

PRN stands for 'pro re nata,' a Latin phrase meaning 'as needed.' On a medication administration record or care plan it marks a medication or treatment that is given only when a stated need arises, rather than on a fixed schedule. Deciding whether a PRN dose is needed is a clinical decision for the registered staff, not the PSW's. The PSW observes — for example, that the client reports pain — and reports it through the approved reporting path.

Which abbreviations are on ISMP Canada's Do Not Use list?

The 2025 Canadian list covers abbreviated medication names; the unit abbreviations U, IU, ug and cc; the frequency and duration forms OD, QD, QOD, EOD, D or d, and x/7 or y/52; the Latin route abbreviations AS, AD, AU and OS, OD, OU; the symbols for less than, greater than and at, and D/C; and dose designations such as Roman numerals, a trailing zero and a missing leading zero. Each entry has an always-use replacement — write units instead of U, daily instead of QD, and millilitre or mL instead of cc — and ask for clarification when you find an ambiguous form such as OD, which can mean daily or right eye.