While yarn is a very simple material made of fibers spun to create a long strand, describing it isn’t always so simple. Besides color, people tend to use certain terms to describe yarn’s weight, its texture, and even its source. Thread is a type of yarn intended for sewing by hand or machine. This guide should help you understand the basic terms you will find on a package of yarn or listed within a set of instructions.
Yarn Types
Natural vs. Synthetic
Many crafters prefer to work with natural fibers both for their texture and that they’re also a renewable resource. How the product will be used is another important consideration since cotton can be highly absorbent making it a good choice for washcloths or towels; keep in mind it’s also highly flammable and can be an allergen for some people.
Synthetic materials are generally less flammable but may melt if exposed to high temperatures. Ultimately, the best material will be one you’re most comfortable working with while meeting any requirements you have for your specific project.
Felting Yarn
For most projects, you want to avoid yarn that pills or turns fuzzy after you wash it. Felting yarn is different since felting intentionally mats the yarn fibers to create a solid block of material. Crafters have used a wide variety of yarns for felting, including synthetics, but loosely spun yarns made from animal fibers are generally the easiest to felt.
Specialty Yarn
This is a rather broad term encompassing any unusual type of yarn, particularly when the fibers are spun to create a pattern or texture in the yarn. Boucle yarn and eyelash yarn are a couple of the most common types of specialty yarn, with tight loops or curls added to the former and long, loose strands threaded through the latter.
Terminology
Skein
A skein is an individual package of yarn. Most instructions will list the number of skeins you need to complete the project. Be careful, though, because the amount of yarn in a skein varies widely. Using a different yarn or a different size of skein could mean you run out too soon.
Weight
Generally this describes how thick the yarn is. Using a yarn that’s too bulky or too fine can change the size of your project. Weight can also be measure in ply, as in 2-ply, 3-ply, or 4-ply yarn, but using standard yarn weight is considered a more reliable measurement.
In this system, yarn is divided into six categories. Crochet thread is the finest, followed by fingering-weight or sock yarn, then baby yarn and sport yarn. Light or light worsted yarn is a bit heavier, while medium weight is known as worsted weight. Bulky yarn is significantly heavier and good for thick projects like rugs, and as the name implies, super bulky is the heaviest yarn available.
Ply
Ply is an older standard for measuring yarn weight. A ply is a twisted strand of fibers that can either be used on its own as singles yarn or twisted again with other plys to form 2-ply, 4-ply, or even 8-ply yarn. The more plys a yarn has, the bulkier it will be, but not all plys are the same weight to start with. In the US, the Standard Yarn Weight System may give you a better idea of the yarn’s actual thickness.