Source : Webster's Revised Unabridged Dictionary (1913)

Tunnel \Tun"nel\, v. t. [imp. & p. p. {Tunneled}or {Tunnelled};
   p. pr. & vb. n. {Tunneling} or {Tunnelling}.]
   1. To form into a tunnel, or funnel, or to form like a
      tunnel; as, to tunnel fibrous plants into nests. --Derham.

   2. To catch in a tunnel net.

   3. To make an opening, or a passageway, through or under; as,
      to tunnel a mountain; to tunnel a river.