There are two meanings for 'ply' with wool. Some wool manufacturers use the term ply to describe the weight of the wool. A 2 ply is a very fine baby wool whereas a 16 ply is a chunky or heavy weight yarn. The other meaning is the number of threads the yarn consists of. For example to a hand spinner a 2 ply means a yarn that has two single threads 'plied' together to form one length of yarn.
The stuffing of a baseball is cotton yarn, 3-ply grey wool yarn,4-ply grey wool yarn, a pill, 3-ply white wool yarn,black rubber, and red rubber.
Your question doesn't make sense. For example: 4-ply yarn is 4 singles plied (twisted and set) together.Lace weight yarn is usually single or 2-ply.
Most 4-ply yarns are medium-weight, which may carry the name worsted weight yarn. Ply is a complicated thing. Thickness and ply of yarn is different depending on where the yarn is manufactured. In the U.S. worsted weight is generally 4 ply. The number of plies is not always an indication of weight, however. It is just tells you how many strands are used in that type of yarn.
sometimes called 2 ply it is thin yarn which produces a thin fabric and is used for knitting lace (among other things)
Yarn that is a single strand is called single-ply or one-ply.
Yes, DK weight (also called double knitting) is 8 ply yarn
two for one, 2 ply (ends) of yarns are twisted to form one.
Patons Ritz yarn was a bulky yarn. It was about 12 ply.http://www.ravelry.com/yarns/library/patons-ritz
The Siro process makes it possible to produce a directly weavable two ply yarn, directly at the ring spinning machine, so eliminating the usual twisting process. From this you get yarn strength, a smooth yarn, minimal hairiness and round yarn cross section
In the UK, worsted weight yarn corresponds to 10ply (i.e. heavy DK or light aran yarn)
"Double knit," refers to the weight or thickness of the yarn. Double knit is between sport weight and worsted weight. It is named for the knitting technique that most often calls for this weight: double knitting. Double knitting is the knitting of a two sided fabric that is reversable with a two color pattern on one side and the negative of that pattern on the reverse side. It is called double knitting because both sides are knit at the same time on one set of needles. "4 ply" refers to the number of individual strands twisted together to form a yarn. A yarn with two strands is called "2 ply," and so on. The number of plies determines, to a degree, the fluffiness or smoothness of a yarn. Yarn with more plies is generally smoother and less fluffy. The number of plies does not determine the weight or thickness of the yarn. It is possible to have a double knit yarn that is also 4-ply, or to have a thicker yarn that is has more or fewer plies. The same is true with a thinner yarn.