It is not equivalent to bisexuality, because it’s broader in scope.
In the old days, it seemed simple: Men hunted and women bore and raised kids. Then we moved out of caves, invented gender studies, and learned a thing or two about genetics. Now nothing is clear cut. While social and biological analyses of gender offend some, they have freed others to finally feel comfortable in their own skin.
Sexual Orientation is a term used to describe our patterns of emotional, romantic, and sexual attraction—and our sense of personal and social identity based on those attractions. A person's sexual orientation is not a black or white matter; sexual orientation exists along a continuum, with exclusive attraction to the opposite sex on one end of the continuum and exclusive attraction to the same sex on the other.