Sexual orientation is defined by the interplay between a person's emotional and physical attraction toward others. Generally, sexual orientation is broken into the three categories: heterosexual, homosexual and bisexual. By basic definition, the term heterosexual is typically used in reference to someone who is attracted to people of the opposite sex, the term homosexual is used to classify people who are attracted to those of the same sex, and the term bisexual is used to identify those who are attracted to both the same and opposite sexes. Sexual orientation can be variously defined based on sexual identity, sexual behavior and sexual attraction. People can fall anywhere on a spectrum from strictly heterosexual to strictly homosexual.