A pronoun is a word used in place of a noun.

Mr. Ishimori is my neighbor.

Ishii is my best friend.

Ishiyama is my best friend.

In this sea area, you can often see Asian paddle crabs.

As for that person, what are they doing?

He found a big stone in the river.

Where does Mr. Ishikawa live?

A common noun refers to a noun that does not point to a specific person or thing.

Her necklace had a beautiful cat's eye stone.