Here is a link to the last post.
There is much more to nouns. As the English language is versatile, you can meet nouns as other parts of speech.
One of the more common forms a noun can take is an adjective. This happens when one noun modifies another (geography teacher); (war story); (grocery store). Geography, war, and grocery are used as adjectives in this case.
Nouns can also become verbs (a phone - to phone); (a remark - to remark); (a matter - to matter). While it might be obvious to native speakers, it doesn't work for everyone. If you are learning, you should pay attention to this trivial stuff.
This concludes the short summary of nouns. Next post will be about pronouns.