What kind of fabric is the 'rib' that frequently appears in product descriptions?

Rib refers to a knit structure woven with repeating vertical ridges. Because it has the property of returning to its original shape after stretching, it is commonly used in areas that take stress when putting on and taking off garments, such as the neck or wrists.

In LOW CLASSIC descriptions, this word appears in three places. The first is the neckline itself. A wide, scooped round neckline is made with rib fabric to help the widely opened neckline maintain its shape^[1]. The second is color. This is when the neck and sleeves are trimmed with ribbing in a different color from the body, in which case the ribbing looks like a line outlining the garment^[2]. The third is the entire surface of the garment. Knitted in a rib structure to complete a three-dimensional pattern, the rib here is not a finishing material for neatening parts, but the fabric that makes up the entire surface^[3].

hmmm, the reason a single structure is placed in such different contexts seems to be that the ridged structure can be used for any of holding, dividing colors, or creating a surface. Therefore, when encountering 'rib' in a description, whether it is on the neck, on the border, or across the entire body determines the impression of the garment, rather than the meaning of the word itself.