Define irregular nouns...

This is what I found from one of the web.

According to Irregular Nouns (2006),irregular noun is
"When irregular nouns change from their singular form to become plural,
their spelling changes, in a different way to regular plural words, where
cat, dog and book are made plural by adding a letter 's' - cats, dogs,
books etc. But it would be incorrect English to add an 's' or 'es' to
'irregular' words."

Retrieved from http://www.examples-help.org.uk/parts-of-speech/irregular-nouns.htm

So, don't forget to define it so that your audiences will have clearer picture on what you are trying to teach! Happy defining! ;)

Next lesson, irregular verb! :)