"plus size" is an awful Orwellian corporate euphemism to psychologically protect people from the fact that they're fat. And I say this as someone who wears XL shirts. It's also the result of the normalization of obesity and being overweight, which is probably due to unethical food producers. It could also be due to skyrocketing depression rates, which are probably due to increasing technology if not to, again, unethical food producers.
It's good that companies are trying to be more accommodating with plus size women, I'm glad this whole "I can't wear that, I'm too big to pull it off" is dying out. But some of their ideas of plus size women is ridiculous, some of them think size 10-12 is plus size.
As in clothing? Or just kinda bigger people in general? I don't guess it matters to me because I want people to find their happiness, whatever size that comes in, waste of life and time trying to police random people's waistlines...and it's not a dealbreaker for me sexually either, if I'm into her I'm into her, saddle up and let's goooo