There are 9 words that start with 'nitrog'.
| nitrogen | nitrogens |
| nitrogenase | nitrogenous |
| nitrogenases | nitroglycerin |
| nitroglycerine | nitroglycerins |
| nitroglycerines | |
Note: These 9 words that start with 'nitrog' are found from the USA & Canada version of the tournament Scrabble word list.