and/or
A conjunction indicating an option or possibility of both things listed ("and") or either thing listed ("or"). The phrase "X and/or Y" could be written out as "X and Y, or X or Y." Come on, we need to celebrate a little bit! Can't we at least have cake and/or ice cream in honor of your birthday?
and/or
Both or either of two options. For example, His use of copyrighted material shows that the writer is careless and/or dishonest. This idiom originated in legal terminology of the mid-1800s.