TUNNEL

I. noun Etymology: Middle English tonel cask, tun, from Anglo-French, from tone tun Date: 1508 a hollow conduit or recess ; tube , well , 2. a covered passageway, a subterranean gallery (as in a mine), burrow , ~like adjective II. verb (-neled or -nelled; -neling or ~ling) Date: 1795 intransitive verb to make or use a ~, to pass through a potential barrier , transitive verb to make a ~ or similar opening through or under, ~er noun