There are 11 words that start with 'catac'.
| catacomb | cataclysm | 
| catacombs | cataclysms | 
| catachreses | catachresis | 
| cataclysmal | cataclysmic | 
| catachrestic | catachrestical | 
| cataclysmically | |
Note: These 11 words that start with 'catac' are found from the USA & Canada version of the tournament Scrabble word list.