One who is sexually attracted to members of the opposite sex.
For some reason some people (def. 2) seem to think that heterosexuals are all homophobic or think other sexual preferences are 'wrong'. Really, most heterosexual people don't have a proplem with homosexuality at all.
Heterosexual is the most common sexual orientation in the world, not because everyone is secretly gay and don't want to come out with it, but because people are born that way. However quite a lot of the new generation are gay or bisexual so this could change soon.
So please don't think that heterosexual people are all completely anit-gay, only straight because it's their religeon, secretly homosexual, or anything like that. Not all heterosexuals make it their life's work to abuse homosexuals. We've usually got better stuff to do.
When I read def 2, I felt ashamed of my heterosexuality. I thought to myself, "This must have been how gay people felt before they were accepted."