Source : Webster's Revised Unabridged Dictionary (1913)

Massicot \Mas"si*cot\, n. [F. massicot; E. masticot is a
   corruption.] (Chem.)
   Lead protoxide, {PbO}, obtained as a yellow amorphous powder,
   the fused and crystalline form of which is called {litharge};
   lead ocher. It is used as a pigment.

Source : WordNet®

massicot
     n : the mineral form of lead monoxide; in the form of yellow
         powder it is used as a pigment [syn: {massicotite}]