According to Dictionary.com the definition of “bipartisan” is the following:
bi-par-ti-san /[bahy-pahr-tuh-zuhn] - adj. representing, characterized by, or including members from two parties or factions.
In the Obama Dictionary Version 2009 the definition is:
bi-par-ti-san /[bahy-pahr-tuh-zuhn] - adj.  a one-way street representing, characterized by, or including members from two parties or factions embracing every presidential agenda item with open [...]