What are the words that contain root word peter?

The root word "peter" doesn't actually exist in English. It's likely you're thinking of the word "petro," which is a Greek root meaning "stone" or "rock."

Here are some words containing the root "petro":

* Petroleum: A liquid mixture of hydrocarbons that is found underground and used as a fuel.

* Petrology: The branch of geology that studies rocks.

* Petrochemical: Relating to or derived from petroleum.

* Petrography: The description and classification of rocks.

* Petrified: Turned into stone.

If you meant a different word, please let me know!