Learning Spanish & Etymology Pattern-Matching for Nerds

Mientras (Spanish for “while”), comes from the Latin dum interim, meaning, “in the meantime,” which itself comes from the earlier basic prefix, inter-. Interim has entered formal English speech meaning the same, of course.

The n‑t-r root is visible in both mientras and interim — but it is less obvious because of the m- opening sound, from the lost prefix dum (“out of”).