The Collaborative International Dictionary of English v.0.48:

Pisasphaltum \Pis`as*phal"tum\, n.
   See Pissasphalt.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Pissasphalt \Pis"sas*phalt\, n. [L. pissasphaltus, Gr. ?; ?
   pitch + ? asphalt: cf. F. pissasphalte.] (Min.)
   Earth pitch; a soft, black bitumen of the consistency of tar,
   and of a strong smell. It is inflammable, and intermediate
   between petroleum and asphalt. [Written also pisasphaltum,
   pisasphalt, etc.]
   [1913 Webster]