There are 11 words that start with 'protoz'.
| protozoa | protozoal |
| protozoan | protozoic |
| protozoon | protozoans |
| protozoons | protozoology |
| protozoologies | protozoologist |
| protozoologists | |
Note: These 11 words that start with 'protoz' are found from the USA & Canada version of the tournament Scrabble word list.