One thing I find encouraging on here!

[Fidel_Castronaut]

No. I asked what it 'means', not for a definition of heterosexuality (what about women who have sex with men?)

I thought we were talking about men, sorry. A straight person is someone who has sex with only members of the opposite sex. That’s what it means.

You're demonstrating only that you know what the definition of heterosexuality is.

You're not demonstrating you know what it 'is' to be straight; what it means. So I conclude that you don't know, and that the concept is 'nonsensical'.