There are 17 words that start with 'psi'.
| psi | psis | psilocin |
| psiloses | psilosis | psilotic |
| psilocins | psilocybin | psilophyte |
| psittacine | psilocybins | psilophytes |
| psilophytic | psittacines | psittacoses |
| psittacosis | psittacotic | |
Note: These 17 words that start with 'psi' are found from the USA & Canada version of the tournament Scrabble word list.