There are 11 words that start with 'serp'.
| serpent | serpigo | 
| serpents | serpigos | 
| serpigoes | serpentine | 
| serpigines | serpentines | 
| serpiginous | serpentinely | 
| serpiginously | |
Note: These 11 words that start with 'serp' are found from the USA & Canada version of the tournament Scrabble word list.