Bisexuality is romantic attraction, sexual attraction or sexual behavior towards two biological sexes or genders, and may also encompass romantic or sexual attraction to people of any gender, which is sometimes termed pansexuality or omnisexuality. Multisexuality is attraction to more than one biological sex or gender, but is not necessarily as encompassing as omnisexuality.
Along with heterosexuality and homosexuality. bisexuality is one of the three main categories of sexual orientation within the heterosexual–homosexual continuum. However, some authorities feel that limiting sexual classification to a linear representation does not reflect the width or depth of sexual attraction and behaviour.