The Collaborative International Dictionary of English v.0.48:

Methylal \Meth"yl*al\, n. [Methylene + alcohol.] (Chem.)
   A light, volatile liquid, H2C(OCH3)2, regarded as a complex
   ether, and having a pleasant ethereal odor. It is obtained by
   the partial oxidation of methyl alcohol. Called also
   formal.
   [1913 Webster]