Meaning

noun a passageway through or under something, usually underground (especially one for trains or cars)

noun a hole made by an animal, usually for shelter

verb move through by or as by digging

originFrom Middle French tonnelle (“net”) or tonel (“cask”), diminutive of Old French tonne (“cask”), a word of uncertain origin and affiliation. Related to Old English tunne (“tun; cask; barrel”). More at tun.

Etymology from Wiktionary, CC BY-SA 3.0