Root words in English have their basic roots from Greek and Latin language. The root words in English are a combination of basic words and additional prefixes and suffixes. Root words in English form a basis of the new word.  Root words in English are parts upon which complete words are built. This usually happens by adding prefixes and suffixes to the word as already mentioned.
Let’s take up an example to understand how root words in English work.  Have you heard of the word Philanthropy? It means love for humanity and refers to various charitable and welfare acts. It is derived from a combination of two Root Words in English:

• Phil which means Love
• Anthop/anthropy which means Mankind or humans

These two root words combine to give us Philanthropy (Love for Humanity).
Now we can extend this learning and add some more words based on the root anthrop:

• Misanthrope: Someone who dislikes people or avoids social situations
• Anthropology: Study of Mankind
• Anthropologist: The persons who involves in the study of anthropology

You can see from the above example that root words in English are a powerful method to learn multiple words at the same time.

List of Must Know Root Words in English

The commonly used root words in English are listed below:
1. Root Word: ambi
Meaning: both
Words: ambidextrous, ambivert

2. Root Word: corp
Meaning: body
Words: corpus, corporal punishment

3. Root Word: inter
Meaning: between
Words: intersect, interject

4. Root Word: gen
Meaning: birth
Words: generation, genesis

5. Root Word: lum
Meaning: light
Words: luminious, luminate

6. Root Word: tele
Meaning: far
Words: telepathy, telephone

7. Root Word: narr
Meaning: to tell
Words: narrate, narrator

8. Root Word: jud
Meaning of the root word in English: judge
Words: judiciary, prejudice

9. Root Word: mort
Meaning: death
Words: mortal, mortuary

10. Root Word: form
Meaning: to shape
Words: conform, reform

11. Root Word: multi
Meaning of the root word in English: many
Words: multitask, multilingual.

12. Root Word: script
Meaning: to write
Words: scripture, manuscript

13. Root Word: semi
Meaning: half
Words: semiconductor, semicircle.

14. Root Word: un
Meaning of the root word in English: not
Words: unreadable, uneatable

15. Root Word: acri
Meaning of the root word in English: bitter
Words: acrimony,acrid

You can see clearly, that the above mentioned list will help you remember more and more words and also help you retain the meanings of these important Root Words in English.