2nd Grade Writing (Common Core) • Language

Prefix Power: Build New Words and Meanings

Learn how to add special word parts to make new words with different meanings!

A writing pencil with notebook and spelling check for elementary writing
Inside this lesson 10 sections 5 questions 5 figures

SECTION 1

How People Started Making New Words

Long, long ago, people needed more words to talk about things. They were smart and found a way to make new words by adding special parts to the front of words they already knew! These special word parts are called prefixes. Just like building with blocks, people could build new words!

Ancient Times • First Word Building

People in old times started adding word parts like un- to make opposite words

Middle Times • More Prefixes

People learned to use re- to mean doing something again

Modern Times • New Prefixes

We use pre- for before and dis- for not or opposite

Today • Learning Fun

Kids like you learn to be word builders using prefixes!

Today we use prefixes all the time to make our talking and writing more interesting. When we know how prefixes work, we can understand new words and make our own!

SECTION 2

What Are Prefixes and How Do They Work?

A prefix is a special word part that goes at the very beginning of a word. It changes what the word means! When you put a prefix in front of a word, you make a brand new word with a different meaning.

1

Prefixes Go First

A prefix always comes at the beginning of a word, just like how you put on your shoes before your socks!
2

Prefixes Change Meaning

When you add a prefix, the word means something different than before. Happy becomes unhappy!
3

Prefixes Have Meanings

Each prefix has its own special meaning. When you learn what a prefix means, you can figure out new words!
4

Many Words Use Prefixes

Lots of words we use every day have prefixes. You probably already know many prefix words!
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KEY TAKEAWAY

Think of prefixes like magic stickers you can put on words! Just like putting a sad face sticker on a happy drawing changes how it looks, putting un- on happy changes how the word feels!

SECTION 3

See How Prefixes Work

How Prefixes Build New Wordsun-prefix+happybase word=unhappynew word!re-prefix+readbase word=rereadnew word!pre-prefix+schoolbase word=preschoolnew word!
This picture shows how prefixes (blue boxes) join with base words (purple boxes) to make new words (pink boxes)!

Look at how the prefix and the base word work together like puzzle pieces! The prefix always goes first, and when they join together, they make a brand new word with a different meaning.

SECTION 4

The Most Important Prefixes to Know

There are many different prefixes, but some are used more than others. Let's learn the most important ones that you'll see and use all the time!

PrefixMeaningExample
un-not, oppositeunhappy (not happy)
re-again, backreread (read again)
pre-beforepreschool (before school)
dis-not, oppositedislike (not like)

The four most common prefixes you should learn first

These four prefixes are like your word-building tools! Once you know what they mean, you can understand lots of new words and make your own. Try to remember: un- and dis- mean the opposite, re- means again, and pre- means before.

SECTION 5

More Fun Examples of Prefixes

Prefix Word Treehappyunhappy (not happy)rehappy? (no!)Some prefixes don't work with all words!doundoredoviewpreviewreview
This word tree shows how different prefixes can be added to base words to make new words. Notice that not all prefixes work with every word!

The word tree shows us something important: not every prefix works with every word! You can't say rehappy because it doesn't make sense. But you can say unhappy, undo, redo, preview, and review because these make sense!

SECTION 6

Let's Build a Word Together

Let's practice building a new word step by step! We'll start with the word tie and add the prefix un- to make a new word.

Building the Word 'Untie'

  1. 1

    Step 1 — Find the Base Word

    Our base word is tie. This means to fasten something with a knot, like tying your shoes.
    Base word: tie
  2. 2

    Step 2 — Choose the Prefix

    We want to add the prefix un-. Remember, un- means 'not' or 'the opposite'.
    Prefix: un-
  3. 3

    Step 3 — Put Them Together

    Now we put the prefix first, then the base word. un- + tie = untie
    New word: untie
  4. 4

    Step 4 — Figure Out the New Meaning

    Since un- means 'the opposite' and tie means to fasten, untie means to unfasten or loosen a knot!
    Meaning: to unfasten a knot

SECTION 7

How to Be a Great Prefix Detective

Sometimes you'll see a word you don't know, but if it has a prefix, you can be a word detective and figure out what it means!

Detective StepWhat to DoExample
1. Look for the PrefixFind the part at the beginningIn 'rewrite', find 're-'
2. Find the Base WordTake away the prefixTake away 're-' and get 'write'
3. Think About MeaningUse what you know about the prefix're-' means again, so 'rewrite' means write again

Your three-step plan for understanding new words with prefixes

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KEY TAKEAWAY

Being a prefix detective is like being a word puzzle solver! When you see a long word, don't panic. Look for the prefix at the beginning, find the base word you already know, and put the meanings together. It's like solving a fun mystery!

SECTION 8

Other Cool Prefixes to Learn Next

Once you know the basic prefixes really well, you can learn some new ones to become an even better word builder!

Beginner PrefixesNext Level Prefixes
un- (not) → unhappyover- (too much) → overeat
re- (again) → rereadunder- (below, not enough) → underwater
pre- (before) → preschoolsuper- (above, great) → superhero
dis- (not, opposite) → dislikeout- (beyond, better) → outrun

Start with the beginner prefixes, then try the next level ones!

Don't try to learn all the prefixes at once! Start with the four beginner ones (un-, re-, pre-, dis-) and practice them lots. When those feel easy, then you can learn the next level prefixes!

SECTION 9

Practice Problems

Question 1: CONCEPTUAL

What is a prefix? Where does it go in a word?
Show answer
A prefix is a special word part that goes at the very beginning of a word. It changes the meaning of the word it's added to. For example, when you add the prefix 'un-' to 'happy', you get 'unhappy' which means the opposite of happy. Prefixes always come first, before the main word!

Question 2: BASIC CALCULATION

Add the prefix 'un-' to these words: lock, safe, kind. What do the new words mean?
Show answer
When we add 'un-' we get: unlock (to open a lock), unsafe (not safe or dangerous), and unkind (not kind or mean). The prefix 'un-' means 'not' or 'opposite', so it makes each word mean the opposite of what it meant before. These new words are very useful in writing and talking!

Question 3: INTERMEDIATE

Look at this word: 'rewrite'. Can you be a word detective? What is the prefix, what is the base word, and what does the whole word mean?
Show answer
Let me be a word detective! The prefix is 're-' (which means again). The base word is 'write'. So 'rewrite' means to write again. If you wrote a story but wanted to make it better, you would rewrite it. The prefix 're-' tells us that someone is doing the writing a second time.

Question 4: APPLIED

Make up three sentences using these prefix words: prehistoric, disagree, redo. Show that you understand what each word means.
Show answer
Here are three sentences: 'Dinosaurs lived in prehistoric times, which means before history was written down.' 'My friend and I disagree about which game to play, so we need to talk about it.' 'I made a mistake on my drawing, so I need to redo it to make it look right.' Each prefix changes the base word's meaning in a special way!

Question 5: CRITICAL THINKING

Why do you think prefixes are so helpful for writers and speakers? Give two reasons and explain each one.
Show answer
Prefixes are helpful for two big reasons. First, they let us make new words quickly without having to learn completely different words. Instead of memorizing a new word for 'not happy', we just add 'un-' to 'happy'! Second, they help us understand new words when we read. If we see 'unfriendly' and know that 'un-' means 'not', we can figure out it means 'not friendly' even if we've never seen that exact word before. Prefixes are like tools that make language easier!

SUMMARY

What We Learned About Prefix Power

Summary

Today we learned about prefixes, which are special word parts that go at the beginning of words to change their meaning. The four most important prefixes to remember are un- (not or opposite), re- (again), pre- (before), and dis- (not or opposite).

When you see a new word with a prefix, you can be a word detective! Look for the prefix at the beginning, find the base word, and put the meanings together. This helps you understand new words and build your own words for better writing and talking!

Varsity Tutors • 2nd Grade Writing • Prefix Power: Build New Words and Meanings