- ento-
- word-forming element used chiefly in biology and meaning "within, inside, inner," from Greek ento-, comb. form of entos (adv., prep.) "within, inside," as a noun, "inner parts" (cognate with Latin intus), from PIE *entos-, extended form of root *en "in" (see in), with adverbial suffix *-tos, denoting origin.
