From Latin suber, apparently from the same Proto-Indo-European root as Old High German swigen (“to be silent”), possibly a reference to cork being stripped without harming the tree.
"suber." YourDictionary, n.d. Web. 17 August 2018. <http://www.yourdictionary.com/suber>.
suber. (n.d.). Retrieved August 17th, 2018, from http://www.yourdictionary.com/suber