Coeliac vs. Celiac... What's the difference?

Trick question: there is none! Coeliac is simply how the word is spelled in Ireland or the UK. It is pronounced the same, so at a restaurant simply ask if they have a special "see-lee-ack" menu or gluten free options. The 'celiac' version is how my fellow Americans spell it. 

Ireland = Coeliac

Irish flag

America = Celiac

American Flag