Bipartisan means involving or supported by members of two (or more) political parties, especially when such cooperation is unusual.
Here's a breakdown:
* Bi- means "two"
* Parti- relates to "party"
* -san is a suffix that indicates "belonging to"
So, bipartisan refers to something that is supported by two parties.
For example, a bipartisan bill is a bill supported by both major political parties.