\Ton`neau"\, n.; pl. {Tonneaux}. [F.]
1. In France, a light-wheeled vehicle with square or rounded
   body and rear entrance.
2. (Automobiles) Orig., the after part of the body with
   entrance at the rear (as in vehicle in def. 1); now, one
   with sides closing in the seat or seats and entered by a
   door usually at the side, also, the entire body of an
   automobile having such an after part.
3. = {Tonne}.