There are 12 13-letter words that start with 'arc'.
| archaeologies | archaeologist |
| archaeopteryx | archbishopric |
| archduchesses | archegoniates |
| archidiaconal | archimandrite |
| archipelagoes | architectonic |
| architectural | architectures |
Note: These 12 13-letter words that start with 'arc' are found from the USA & Canada version of the tournament Scrabble word list.
Also see words start with arch, arca, arcu, arct, arcs, arcc, arci, arck, arce, arco.
4-letter words start with 'arc' (3)