There are 3 12-letter words that start with 'ran'.
| rancidnesses | randomnesses | ranunculuses | 
Note: These 3 12-letter words that start with 'ran' are found from the USA & Canada version of the tournament Scrabble word list.
Also see words start with ranc, rand, rank, rang, rans, rant, ranu, rani, rane, ranp.
4-letter words start with 'ran' (5)