Where does “интегра́л” come from?

интегра́л (Russian) comes from Medieval Latin integralis, from Latin integer, from Proto-Italic *n̥tagros.

Ancestry of “интегра́л”, step by step

Step	Language	Word	Meaning
1	Medieval Latin	integralis	integral; complete
2	Latin	integer	complete, whole, intact; uninjured, sound,...
3	Proto-Italic	*n̥tagros	—

интегра́л — Etymology, Origin & Word History | Etymology Explorer