What is a root word?
A root word is the main part of a word that carries its basic meaning. Prefixes and suffixes attach to roots, like branches growing from a tree’s roots.
Some roots are complete words on their own, like play in replay. These are often called base words. Many other roots cannot stand alone. They come from older languages, especially Greek and Latin, and appear in hundreds of English words.
For example, the Latin root port means carry:
- transport: carry across
- portable: able to be carried
- import: carry in
- export: carry out
- porter: a person who carries luggage
Once you know port, you have a key to a whole word family.
Why roots are so useful
About half of English words come from Latin or Greek. Science, math and social studies words especially use these roots. If you know a few dozen roots, you can make smart guesses about thousands of words, including big ones like thermometer, biography and interrupt.
Common Latin roots
| Root | Meaning | Examples |
|---|---|---|
| port | carry | transport, portable, report |
| rupt | break | erupt, interrupt, rupture |
| struct | build | construct, structure, instruct |
| dict | say, speak | predict, dictionary, contradict |
| spect | look, see | inspect, spectator, respect |
| scrib, script | write | describe, scribble, manuscript |
| vis, vid | see | vision, visible, video |
| aud | hear | audio, audience, audible |
| ject | throw | eject, project, reject |
| tract | pull, drag | tractor, attract, subtract |
| form | shape | transform, formation, uniform |
| mit, miss | send | transmit, mission, submit |
Common Greek roots
| Root | Meaning | Examples |
|---|---|---|
| graph | write, draw | autograph, paragraph, photograph |
| photo | light | photograph, photosynthesis |
| tele | far | telephone, telescope, television |
| phon | sound | phonics, microphone, symphony |
| bio | life | biology, biography |
| geo | earth | geography, geology |
| micro | small | microscope, microphone |
| scope | see, look | telescope, microscope |
| therm | heat | thermometer, thermos |
| auto | self | automatic, autobiography |
| meter | measure | thermometer, centimetre |
| logy | study of | biology, zoology |
Putting roots together
Greek roots often combine with other roots:
- tele (far) + scope (see) = telescope: a tool to see far away.
- micro (small) + scope (see) = microscope: a tool to see small things.
- bio (life) + graph (write) = biography: writing about someone’s life.
- auto (self) + bio + graph = autobiography: writing about your own life.
- therm (heat) + meter (measure) = thermometer: a tool to measure heat.
How to use roots to understand a word
- Remove any prefix and suffix.
- Find the root that is left.
- Recall the root’s meaning. Think of other words with that root.
- Add back the prefix and suffix meanings.
- Check the meaning in the sentence.
Worked examples
Example 1: inspector
in- (into) + spect (look) + -or (person who) = a person who looks into things.
Example 2: eruption
e- (out) + rupt (break) + -ion (act of) = the act of breaking out.
The volcano’s eruption sent ash into the sky.
Example 3: audible
aud (hear) + -ible (can be) = able to be heard.
Her whisper was barely audible.
Example 4: geography
geo (earth) + graph (write, describe) + -y = describing the earth.
Example 5: construction
con- (together) + struct (build) + -ion = the act of building things together.
Roots across your subjects
Roots show up in every subject at school.
- Science: hydro (water) in hydrant and dehydrated; bio in biome; therm in thermal.
- Math: tri (three) in triangle; cent (hundred) in centimetre and century; meter in perimeter, the measure around a shape.
- Social studies: demo (people) in democracy; geo in geography; port in import and export.
When you meet a new word in a textbook, ask, “Do I see a root I know?” Even if you can only figure out part of the word, that part often gives you enough to understand the sentence. Then check the glossary to be sure.
A word’s history
The study of where words come from is called etymology. Many dictionaries include a word’s etymology. Looking it up can be surprising and fun. For example, salary comes from the Latin word for salt, because Roman soldiers were sometimes given money to buy salt.
Common mistakes
- Assuming every matching letter pattern is a root. Port in portrait is not about carrying. Always check the meaning in context.
- Mixing up similar roots. Spect (look) and spec in special are different. Use a dictionary if unsure.
- Forgetting the prefix or suffix. Predict (say before) and contradict (say against) share a root but mean different things.
Try it yourself
- What do telephone, telescope and television have in common?
- Use roots to define biology.
- What does rupt mean? Use it to explain interrupt.
- Name two words with the root aud.
- Build a word that means “a tool for seeing small things.”
Answers: 1. They all have tele, meaning far. 2. The study of life. 3. Break; to break into someone’s speaking. 4. Some answers: audio, audience, audition, auditorium. 5. microscope.
Study tip
Create a “root tree” poster. Write a root on the trunk, and add words with that root on the branches as you find them in science, math and reading. Review one root a day.
Quick recap
- A root carries the main meaning of a word.
- Many roots come from Greek and Latin.
- Words that share a root form a word family with related meanings.
- Remove prefixes and suffixes to find the root.
- Knowing roots unlocks vocabulary in every subject.