What is En theos?

Answer:

Literally 'En theos' is the English language equivalent of the Greek words which mean 'in God.'

Furthermore, the word Enthusiasm, arrives from the greek word enthusia, which by turn arrives from the word En theos. so when we say that we feel enthusiasm, it means that at that moment we feel like we have God inside us.

In Greek letters: En Theos= Εν Θεός, Enthusiasm=Ενθουσιασμός