There are 12 words that start with 'thall'.
| thalli | thallic | thallus |
| thallium | thalloid | thallous |
| thallious | thalliums | thalluses |
| thallophyte | thallophytes | thallophytic |
Note: These 12 words that start with 'thall' are found from the USA & Canada version of the tournament Scrabble word list.