gunnysack
I've known the word "gunnysack" (for a burlap bag) since I was a kid, but it was only a few days ago that it finally occurred to me to wonder where the term came from. Turns out it's from "gunny," an Indo-Aryan-derived word referring to coarse fabric; there are related words in Hindi and Punjabi.
Specifically, I think "gunny" is a fabric made from jute (the plant fiber, not the Germanic people). I've know the word "jute" since I was a kid, too, but I never had a clear idea of what it was or what it was used for 'til I read that Wikipedia article recently.