What is ribbed fabric?  It is a knitted fabric with a rib pattern.

Rib knit is a double-knit fabric that knits the fabric in vertical ridged pattern called ribbing and highly stretched in crosswise direction. Rib fabric is often used in round necks and cuffs for certain types of T-shirts.

Ribbing is notated by (number of knit stitches) × (number of purl stitches). Thus, 1×1 ribbing has one knit stitch, followed by one purl stitch, followed by one knit stitch, and so on.

Ribbing has a strong tendency to contract laterally, forming small pleats in which the purl stitches recede and the knit stitches come forward. Thus, ribbing is often used for cuffs, sweater hems and, more generally, any edge that should be form-fitting. The elasticity depends on the number of knit/purl transitions; 1×1 ribbing is more elastic than 2×2 ribbing, etc. However, some cable patterns may "pull in" more than ribbing (i.e., have a smaller gauge); in such cases, a ribbed border may flare out instead of contracting.

In knitting, ribbing is a pattern in which vertical stripes of stockinette stitch alternate with vertical stripes of reverse stockinette stitch.

• Stockinette stitch (in UK, Australia, New Zealand etc., stocking stitch) is the most basic knitted fabric; every stitch (as seen from the right side) is a knit stitch. In the round, stockinette stitch is produced by knitting every stitch; by contrast, in the flat, stockinette stitch is produced by knitting and purling alternate rows. Stockinette-stitch fabric is very smooth and each column ("wale") resembles a stacked set of "V"'s. It has a strong tendency to curl horizontally and vertically because of the asymmetry of its faces.
• Reverse stockinette stitch is produced in the same way as stockinette, except that the purl stitches are done on the right side and the knit stitches on the wrong side.  In the round, reverse stockinette stitch is produced by purling every stitch.

Rib requires two sets of needles operating in between each other so that wales of face stitches and wales of back stitches are knitted on each side of the fabric.

You may want to also learn about twill and corduroy.

In our women's cotton corduroy pants guide, you can also learn about the wale on fabric.

Learn more about fabric.

Learn about knit fabrics.

Learn about woven fabrics.