Bi

[Justin Bieber]

A person with significant attraction and desire for both sexes, both sexually and romantically. (The desire for the two sexes is not necessarily equal.)
Being bi does NOT imply confusion, wanting/having more than one partner, or participation in wild sex orgies.
Short for [bisexual].

[Jessica]

A shortened version of the word bisexual.

[Justin Bieber]

Bi people are attracted to both girls and guys. The attraction is romantic as well as sexual. It is a full relationship with deep feelings.
The word bi is from bisexual which is just too long and not nearly as cool, lol.
There are many bi myths like that they cannot be loyal or are confused which is untrue. Being loyal is a choice anybody can make, bi, straight, gay, lesbian, or whatever. And they are not confused, not anymore then anybody else.
There is a difference between bisexual (or bi) and bi-curious also. Bi-curious is only being curious about what it would be like to be with somebody of the same sex. Bisexuals are not curious (well not in that way). They know who they are attracted to.

[Britney]

1. The state of being bisexual.
2. Latin for two.

[Little_Girl]

Someone who is bisexual

[Merna]

Two; having two.