There are 8 15-letter words that start with 'rein'.
| reincorporating | reincorporation | 
| reindustrialize | reinstallations | 
| reintroductions | reinvestigating | 
| reinvestigation | reinvigorations | 
Note: These 8 15-letter words that start with 'rein' are found from the USA & Canada version of the tournament Scrabble word list.
Also see words start with reins, reinv, reinf, reint, reind, reinc, reinj, reinn, reino, reini, reinh, reink, reine, reinl.
5-letter words start with 'rein' (2)