Bipartisan is a two-part word. The first element is the prefix bi-, which means "two"; the second is partisan, a word that traces through Middle French and north Italian dialect to the Latin part- or pars, meaning "part." Partisan itself has a long history as a word in English. It has been used as a noun in reference to a firm adherent to a party, faction, or cause (especially one exhibiting blind, prejudiced, and unreasoning allegiance), since the 16th century. The related adjective (meaning "of, relating to, or characteristic of a partisan") appeared in the 19th century, as did, after a space of some 50 years, the adjective bipartisan.
