The Collaborative International Dictionary of English v.0.48:

Tetrol \Tet"rol\, n. [Tetra- + benzol.] (Chem.)
   A hypothetical hydrocarbon, C4H4, analogous to benzene; --
   so called from the four carbon atoms in the molecule.
   [1913 Webster]

   Tetrol phenol, furfuran. [Obs.]
      [1913 Webster]