There are 16 words that start with 'flagel'.
| flagella | flagellar | 
| flagellin | flagellum | 
| flagellant | flagellate | 
| flagellins | flagellums | 
| flagellants | flagellated | 
| flagellates | flagellating | 
| flagellation | flagellantism | 
| flagellations | flagellantisms | 
Note: These 16 words that start with 'flagel' are found from the USA & Canada version of the tournament Scrabble word list.