Yarn weight refers to the thickness of yarn used by knitters, weavers, crocheters and other fiber artists.
Different yarn weights. From left to right: Top row - Chunky, super bulky. Bottom row - Fingering, sport, worsted.
Knitting is a method for production of textile fabrics by interlacing yarn loops with loops of the same or other yarns. It is used to create many types of garments. Knitting may be done by hand or by machine.
Woman knitting
Basic pattern of warp knitting. Parallel yarns zigzag lengthwise along the fabric, each loop securing a loop of an adjacent strand from the previous row.
A modern knitting machine in the process of weft knitting
A dropped stitch, or missed stitch, is a common error that creates an extra loop to be fixed.