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📚 English and Language Usage · Using Language and Vocabulary · Lesson 3 of 6 · 5 min

Prefixes: hyper-, hypo-, brady-, tachy- and more

🧩 One prefix can unlock dozens of medical words. Hypoglycemia, hypothermia and hypotension all start with the same clue: below normal.

💡 Key idea

Strip off the prefix first: it often tells you direction, amount, speed or position before you even reach the root.

🧠 The idea

A PREFIX is a word part attached to the FRONT of a word to change its meaning. Core prefixes to know: HYPER- (above, excessive) and HYPO- (below, deficient); BRADY- (slow) and TACHY- (fast); PERI- (around); ENDO- (within, inside); INTER- (between) and INTRA- (within); SUB- (under, below); TRANS- (across, through); ANTI- (against); DYS- (difficult, painful, abnormal); POLY- (many); A- or AN- (without, not). Everyday prefixes include UN- and IN- (not), PRE- (before), POST- (after), RE- (again) and MIS- (wrongly). To read a new word, split off the prefix, find the root, then combine: "tachy" (fast) + "cardia" (heart condition) = a fast heart rate. Watch the look-alikes: inter- means between two things, intra- means inside one thing; hyper- is too much, hypo- is too little.

✏️ Worked example

What does intravenous mean? Split it: intra- (within) + ven (vein) + -ous (relating to). So intravenous means within a vein, as in a medicine given through an IV. Compare intercostal: inter- (between) + cost (rib) + -al (relating to) = between the ribs. Same idea of position, different prefix, different meaning.

📌 Takeaways

  • hyper- = too much; hypo- = too little.
  • brady- = slow; tachy- = fast.
  • inter- = between; intra- = within; trans- = across; peri- = around.

📖 Terms in this lesson

a-, an-: Without or not, as in apnea (absence of breathing) and anuria (no urine output).

ab-: Away from, as in abduction (moving a limb away from the body's midline).

ad-: Toward, as in adduction (moving a limb toward the body's midline).

anti-: Against or opposing, as in antipyretic (a medicine that works against fever).

auto-: Self, as in autoimmune (the immune system attacking the body's own tissue).

bi-: Two or twice, as in bilateral (on both sides).

brady-: Slow, as in bradycardia (a slow heart rate).

contra-: Against or opposite, as in contraindication (a reason not to give a treatment).

de-: Remove, reverse or down, as in dehydration (loss of water from the body).

dys-: Difficult, painful or abnormal, as in dysphagia (difficulty swallowing).

endo-: Within or inside, as in endoscopy (looking inside a hollow organ with a scope).

epi-: Upon or above, as in epidermis (the outer layer of the skin).

✅ Check yourself

Question 1 of 3

Using prefixes, what does bradycardia most likely mean?

  1. A fast heart rate
  2. Inflammation of the heart
  3. A slow heart rate
  4. An irregular heart rhythm
Show the answer and rationale

Answer: C

Brady- means slow and cardia refers to the heart, so bradycardia is a slow heart rate. A fast heart rate would use tachy-, and inflammation would use the suffix -itis.

Question 2 of 3

Which prefix means "between"?

  1. inter-
  2. intra-
  3. peri-
  4. endo-
Show the answer and rationale

Answer: A

Inter- means between, as in interstate (between states). Intra- and endo- both mean within, and peri- means around, so none of them describes being between two things.

Question 3 of 3

A drug is described as antiemetic. Emesis means vomiting. What does the drug do?

  1. Works against vomiting
  2. Causes nausea and vomiting
  3. Slows the digestion of food
  4. Increases the appetite
Show the answer and rationale

Answer: A

Anti- means against, so an antiemetic works against vomiting. A drug that causes vomiting would be the opposite, and nothing in the word refers to digestion speed or appetite.

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