Anyone knows what is Jersey Round Neck?

Probably fabric type.

Here in the Mid-West USA, I think of Jersey as a brand name.

Isn't "jersee" the brand? I think of Jersey fabric, round neck as a style ( compare to V-neck)

I would assume they mean a jersey knit like these:

Sharon

Yes, but that's a breed of cow. ;-)

Jersey is a type of fine stretch knitted fabric. Jersey fabric can be made from silk, cotton, wool and other fibres and is prized for it's excellent draping ability and smooth hand. Round is the collar/neck shape, and would think "T-Shirt" needs no explanation.

Jersey is an island off the Channel Islands and before their cows, Jersey was famous for their knitted goods including stockings. Such items were invariably referred to as "Jersey.....". Jersey knits were long used for men's sportswear (the famous Lactose "polo" shirt was created from Jersey knit), and undergarments, but it was not until Coco Chanel began using it for women's wear that the fabric took off. Long considered "poverty fabric" and good only for men's undergarments, etc, Chanel saw use of the light, easily drape and fitting fabric as just the thing for her designs that were everything current Edwardian fashions were not; comfortable to wear and easy for women to move about in. Many of Mlle Chanel's designs were heavily borrowed if not outright copied from men's wear of the day, and these fashions helped finally bring an end to corsets, boning, and all the frou-frou women's fashions had been up until then. Not until Dior's "New Look" would women be again faced with clothing designed for them to fit it, rather than the other way round.

Candide

Oh I think you're right! I'm not a brand name shopper...:)