Suffixes: -ous, -tion and -sion

For grown-ups: this lesson in words

Years 3 to 6 · English

Suffixes: -ous, -tion and -sion: I can add the suffixes ous, tion, sion and ation, and double a letter when the last part is loud.

1. A suffix is an ending we add to a root word. Here is the root word danger.

   Just add ous. The root word danger does not change.

   danger add ous makes dangerous. The suffix ous means full of: full of danger.

   Picture: The root word "danger" and the suffix "ous" join to make "dangerous". It means "Full of danger".

2. Here is the root word fame. It ends in e.

   ous starts with a vowel, so we drop the e first.

   fame add ous makes famous. Famous means full of fame: known by lots of people.

   Picture: The root word "fame" and the suffix "ous" join to make "famous", dropping the e first. It means "Full of fame: known by lots of people".

3. Your turn: Add the suffix ous to poison. Which spelling is right?

   Choose one:

   • poisonous
   • poisonus
   • poisonnous

   Answer

   The answer: poisonous

   poisonous. Just add ous to poison. It means full of poison.

   Picture: The root word "poison" and the suffix "ous" join to make "poisonous". It means "Full of poison".

Words to know

suffix:

An ending added to a root word.

root word:

The word we start with, before adding a suffix.

vowel:

One of the letters a, e, i, o, u.

noun:

A naming word: a person, place or thing.

verb:

A doing word.