There are 16 words that start with 'diac'.
| diacid | diacids |
| diacetyl | diacidic |
| diaconal | diacetyls |
| diachrony | diaconate |
| diacritic | diactinic |
| diachronic | diaconates |
| diacritics | diachronies |
| diacritical | diachronically |
Note: These 16 words that start with 'diac' are found from the USA & Canada version of the tournament Scrabble word list.