There are 11 11-letter words that start with 'sid'.
| sidednesses | sidedresses | siderolites | 
| sidesaddles | sideslipped | sidestepped | 
| sidestepper | sidestrokes | sideswiping | 
| sidetracked | sidewinders | |
Note: These 11 11-letter words that start with 'sid' are found from the USA & Canada version of the tournament Scrabble word list.
Also see words start with side, sidl, sidd, sidh, sidi.
4-letter words start with 'sid' (2)