Pit"ta*cal (pĭt"tȧ*kăl),
n. [Gr. pi`tta, pi`ssa, pitch
+ kalo`s beautiful: cf. F. pittacale.]
(Chem.) A dark blue substance obtained from wood tar. It
consists of hydrocarbons which when oxidized form the orange-yellow
eupittonic compounds, the salts of which are dark blue.