Source : Webster's Revised Unabridged Dictionary (1913)

Orthocarbonic \Or`tho*car*bon"ic\, a. [Ortho- + carbonic.]
   (Chem.)
   Designating a complex ether, {C.(OC2H5)4}, which is obtained
   as a liquid of a pleasant ethereal odor by means of
   chlorpicrin, and is believed to be a derivative of the
   hypothetical normal carbonic acid, {C.(OH)4}.