This may seem like a really dumb post, but I'm in a fashion class at a non-fashion university and someone gave a presentation on haute couture evening wear. She used J. Lo's Versace dress (the neck plunging one) as an example of celebrity endorsement of a couture dress. But, I thought that dress would be considered RTW and I said this in class. She also said that Ralph Lauren evening dresses would be on par with the Parisian couture dresses and I was like I don't think that's so. Then some know-it-all girl said that dresses displayed on the RTW runway but never mass produced are considered couture pieces. And I just thought that was crazy. So I'd really appreciate if someone could clear up my confusion and be nice to me even if you think it's a silly question 
