There are 14 words that start with 'petrol'.
| petrol | petrols |
| petrolic | petroleum |
| petrology | petrolatum |
| petroleums | petrologic |
| petrolatums | petrologies |
| petrologist | petrological |
| petrologists | petrologically |
Note: These 14 words that start with 'petrol' are found from the USA & Canada version of the tournament Scrabble word list.