There are 13 words that start with 'protot'.
| prototype | prototroph |
| prototypal | prototyped |
| prototypes | prototypic |
| prototrophs | prototrophy |
| prototyping | prototrophic |
| prototypical | prototrophies |
| prototypically | |
Note: These 13 words that start with 'protot' are found from the USA & Canada version of the tournament Scrabble word list.