I read from dex to dextranase.

The month that Muslims take a pilgrimage to Mecca is "Dhu al-Hijja".

https://en.wikipedia.org/wiki/Dhu_al-Hijja

"Diabase" is the preferred name of these types of rocks in North America, but per usual, the rest of the English speaking world prefers to the use the name "dolerite". 

https://en.wikipedia.org/wiki/Diabase

The word of the episode is "diabetes".

You have many places to go to learn more about diabetes! The last link talks more about the etymology. 

h ...