<https://mobile.twitter.com/OED> · 9m <https://mobile.twitter.com/OED/status/1098477455856168960> OED Word of the Day: impervium, n. In science fiction: a virtually impenetrable or indestructible substance (link: http://www.oed.com/view/Entry/378143) oed.com/view/Entry/378… <https://t.co/gvWNuI9D5l?amp=1>