Lookups spiked on Saturday, January 8, 2011.
At a press conference in Tucson after the shooting of Representative Gabrielle Giffords, the Sheriff handling the investigation used vitriol to describe partisan political rhetoric and an "atmosphere of hatred and bigotry" that he felt contributed to the tragedy.
Vitriol means "something caustic" or "virulence of feeling or of speech" - specifically "harsh and angry words."
At its root, vitriol has more to do with chemistry than politics. It comes from the Latin for "glassy" and was originally used to describe something highly corrosive and destructive, like sulfuric acid.