mid-15c., "funnel-shaped net for catching birds," from Middle French tonnelle "net," or tonel "cask," diminutive of Old French tonne "tun, cask for liquids," possibly from the same source as Old English tunne (see tun).
Sense of "tube, pipe" (1540s) developed in English and led to sense of "underground passage," which is first attested 1765, about five years after the first modern tunnel was built (on the Grand Trunk Canal in England). This sense subsequently has been borrowed into French (1878). The earlier native word for this was mine. Meaning "burrow of an animal" is from 1873. Tunnel vision first recorded 1949. The figurative phrase light at the end of the tunnel is attested from 1922.