There are 12 13-letter words that start with 'arch'.
| archaeologies | archaeologist |
| archaeopteryx | archbishopric |
| archduchesses | archegoniates |
| archidiaconal | archimandrite |
| archipelagoes | architectonic |
| architectural | architectures |
Note: These 12 13-letter words that start with 'arch' are found from the USA & Canada version of the tournament Scrabble word list.
Also see words start with archi, archa, arche, archd, archo, archb, archf, archn, archp, archr, archw, archl.
6-letter words start with 'arch' (6)