I read from dinucleotide to dioptric.

A Diode is used in electrical thingies. 

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

It looks like many stories have been written about Diomedes.

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

If I understand the basics, a Diopter is a unit of thickness of a lens that determines how far away from the lens the light focuses. 

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

The word of the episode is "Dionysus".

Wow! Dionysus is the god of m ...