What's the difference between i.e. and e.g.?
word-forming element meaning "within, inside, inner," from Greek ento-, comb. form of entos "within, inside" (cognate with Latin intus), from PIE *entos, from *en "in" (see in) + adverbial suffix -tos, denoting origin.
ento- or ent-
Inside; within: entozoon.