Since alternating current and direct current are two forms of electricity that are incompatible despite being equally powerful, the metaphor of A/C vs D/C can express that idea fairly well. It does not require nor exclude a further meaning involving sexual orientation . Back-to-front suggests a single item that is the wrong way around or has been reversed, like a shirt with the buttons at the back, or holding a map up the wrong way. Back-to-back suggests two things touching each other, and unlike in back-to-back housing, the orientation doesn't necessarily matter, especially for abstract terms like agreements and arrangements (in this context). In common usage (which at the end of the day is what matters - we communicate to get a point across), heterosexual and straight are synonymous. That is, if a person is described as either, they are assumed to be exclusively attracted to the opposite gender; if a relationship is described as such ("He's in a heterosexual relationship right now"), generally it only implies that this particular relationship is one between a male and a female. In terms of expressing attraction to one gender ... I frequently see these two words in 3D programming. For example: the direction of the directional light the orientation of camera So, what’s the difference between them?
