There are 10 words that start with 'decel'.
| deceleron | decelerate | 
| decelerons | decelerated | 
| decelerates | decelerator | 
| decelerating | deceleration | 
| decelerators | decelerations | 
Note: These 10 words that start with 'decel' are found from the USA & Canada version of the tournament Scrabble word list.