There's a new trend called "alpha sizing," in which designers are doing away with numerical sizes in favor of "small," "medium," "large," "extra large," and the rest.
The reason, according to the Wall Street Journal: Alpha sizing makes manufacturing easier, and it also makes things easier for those of us who shop online.
Consumers won't buy two sizes, then return one of them. It's the athletic apparel approach to designer fashion.
Recent data suggests men seem to prefer it as well.