Glossary
A plain-language reference for fiber processing terms. If you are new to working with fiber mills, start here.
A
- Alpaca
- A South American camelid raised for its fiber. Alpaca fiber is softer than most sheep wool, hypoallergenic, and comes in over 20 natural colors. Two breeds: Huacaya (fluffy, crimpy) and Suri (silky, lustrous). Mills processing alpaca need different equipment settings than those for sheep wool.
- Angora
- Fiber from Angora rabbits (not Angora goats – that is mohair). Extremely soft and fluffy with a distinctive halo. Usually blended with wool or silk for strength, since pure angora is slippery and difficult to spin on its own.
B
- Batch separation
- Processing your fiber separately from other customers’ fiber, so your finished product is made only from your fleece. Important for small flock owners who want yarn from their specific animals. Not all mills offer this – ask before sending fiber.
- Batts
- Flat sheets of carded fiber, typically 12 to 36 inches wide. Used for felting, quilting, or woolen-style spinning. Batts produce lofty, warm yarn with more texture than roving. Good for color blending because layers of different fibers can be carded together. See our guide: Roving vs Batts.
- Blend
- A mix of two or more fiber types, combined during carding. Common blends include merino/silk (softness plus sheen), alpaca/wool (warmth plus elasticity), and wool/mohair (structure plus luster). Mills that offer custom blending can create blends to your specifications.
- Bump
- A large quantity of roving wound into a round bundle, typically 1 to 4 pounds. The standard packaging format for mill-produced roving.
C
- Carding
- The process of passing fiber through wire-covered rollers to open, blend, and loosely align the fibers. Produces roving or batts. Carded fiber has fibers oriented in multiple directions, which creates lofty, woolen-style yarn. Most mills use industrial drum carders that process fiber much faster than hand carders.
- Cashmere
- The fine undercoat of cashmere goats. One of the softest natural fibers, with a diameter of 15 to 19 microns. Expensive because each goat produces only 4 to 6 ounces of usable cashmere per year. Requires dehairing to separate the fine undercoat from the coarse guard hair.
- Combing
- A more precise form of fiber alignment than carding. Combing removes short fibers (called noils) and aligns the remaining fibers parallel to each other. The result is called top. Combed fiber produces smooth, strong, worsted-style yarn. Not all mills offer combing – it requires separate equipment.
- Core spinning
- Spinning fiber around a central core thread (usually a strong, thin yarn). Creates a bulky yarn with consistent structure. Some mills offer core-spun yarn as a service, which uses less fiber per yard than traditional spinning.
- Corriedale
- A dual-purpose sheep breed producing medium-fine wool (25 to 31 microns). Popular with beginners because it is forgiving to spin and takes dye well. A good all-around fiber for knitting, weaving, and felting.
D
- Dehairing
- Mechanically separating fine undercoat fiber from coarse guard hair. Essential for processing cashmere, yak, bison, and some llama fiber. Not all mills have dehairing equipment – this is a specialty service.
- Drafting
- The process of pulling and thinning fiber during spinning to control yarn thickness. In mill spinning, drafting is done mechanically by rollers that pull the roving thinner before it receives twist.
- Dryer balls
- Tightly wound and felted balls of wool used in clothes dryers as a natural alternative to dryer sheets. A common product made from wool batts or roving. Some mills sell them as finished products.
- Drum carder
- The machine used for carding. Industrial drum carders have large cylinders covered in wire teeth (called card clothing) that open and blend fiber. Mills use drum carders much larger than hobby hand carders – typically 24 to 72 inches wide.
F
- Felting
- The process of matting fiber together using heat, moisture, and agitation. Wool felts naturally because the scales on the fiber lock together when disturbed. Felting can be intentional (making felt fabric) or accidental (ruining a sweater in the wash). Batts are the standard fiber preparation for felting projects.
- Fleece
- The complete wool coat shorn from a sheep or other fiber animal in one piece. A single sheep fleece weighs 4 to 12 pounds depending on the breed. Raw fleece contains lanolin, dirt, and vegetable matter that are removed during scouring.
- Fulling
- Controlled felting of knitted or woven fabric to shrink and thicken it. Creates a denser, more water-resistant fabric. Some mills offer fulling as a finishing service for handwoven or knitted items.
G
- Grease weight
- The weight of raw, unwashed fleece including lanolin and dirt. Mills that price by grease weight charge based on what you send in, not what comes out after washing. Important to understand when comparing pricing between mills.
- Guard hair
- The coarse outer coat on double-coated animals like llamas, cashmere goats, and bison. Guard hair must be removed (dehaired) before the soft undercoat can be processed. Leaving guard hair in creates a scratchy, unpleasant finished product.
L
- Lanolin
- The natural grease in sheep wool that waterproofs the fleece on the living animal. Removed during scouring. Lanolin accounts for 15 to 25 percent of raw fleece weight. Some spinners prefer to work with fiber that retains some lanolin (“spinning in the grease”).
- Loft
- The fluffiness or springiness of fiber or yarn. High-loft yarn traps more air, making it warmer for its weight. Woolen-spun yarn from batts has more loft than worsted-spun yarn from roving or top.
M
- Merino
- A sheep breed producing some of the finest wool available (17 to 24 microns). Extremely soft and suitable for next-to-skin wear. Merino is the benchmark for softness in the wool world but is more delicate than coarser breeds and can pill with wear.
- Micron count
- The diameter of individual fiber strands, measured in microns (one millionth of a meter). Lower micron count means finer, softer fiber. Under 20 microns is very fine (merino, cashmere). 25 to 30 is medium (Corriedale, Romney). Over 35 is coarse (some longwools, carpet wool). Mills use micron count to determine processing settings.
- Minimum order
- The smallest amount of fiber a mill will accept for processing. Commonly 3 to 20 pounds, though some mills accept as little as 2 pounds. Minimums exist because it takes the same setup time to run 2 pounds as 20 pounds through the equipment. Also called MOQ (minimum order quantity).
- Mohair
- Fiber from Angora goats (not Angora rabbits – that is angora). Lustrous, strong, and dye-fast. Often blended with wool for sheen and durability. Kid mohair (from young goats) is finer and softer than adult mohair.
N
- Neps
- Small knots or tangles in carded fiber, often caused by second cuts during shearing or by fiber that was partially felted before processing. Too many neps make yarn bumpy and uneven. Good skirting before sending fiber to a mill reduces neps.
- Noils
- Short fibers removed during combing. Noils are the waste product of making top but can be used for felting, stuffing, or blending into batts for textured yarn.
P
- Picking
- Opening up washed fiber and removing remaining debris before carding. A picker uses metal teeth to pull fiber apart into a fluffy cloud. This step improves carding quality, especially for fiber with vegetable matter.
- Pin drafting
- An additional processing step after carding that further aligns fibers in roving. Pin-drafted roving (P.D.R.) is smoother and easier to spin than standard roving off the card (R.O.C.). Some mills offer both options at different price points.
- Plying
- Twisting two or more single strands of yarn together. Plying adds strength, balances the twist (so the yarn does not curl), and can create visual effects. Two-ply is most common from mills, but 3-ply and 4-ply are available. Each additional ply uses proportionally more fiber.
R
- Romney
- A longwool sheep breed producing strong, durable fiber (29 to 36 microns). Good for outerwear, rugs, bags, and anything that needs to hold up to wear. Not as soft as merino but much more durable. The long staple length makes it easy to spin.
- Roving
- A continuous rope of carded fiber, roughly 1 to 2 inches in diameter. The standard preparation for spinning smooth, worsted-style yarn. Mill-produced roving is more consistent than hand-carded roving. See our guide: Roving vs Batts.
S
- Scouring
- Washing raw fleece to remove lanolin, dirt, and debris. Done in hot water with a mild detergent, typically in multiple baths. Temperature control is critical – too hot felts the fiber, too cool leaves lanolin behind. Expect to lose 30 to 50 percent of the raw weight during scouring.
- Second cuts
- Short fiber pieces created when the shearer goes over the same area twice. Second cuts create neps in carded fiber and reduce yarn quality. Remove them during skirting before sending fiber to a mill.
- Singles
- A single strand of spun yarn, before plying. Some yarn is sold as singles (single-ply), which has more drape and softness but less strength than plied yarn. Singles yarn tends to bias (twist to one side) in knitted fabric.
- Skirting
- Removing unusable parts of a fleece: belly wool, leg wool, tags (manure-matted fiber), heavily contaminated sections, and short or felted fiber. Done on a skirting table with mesh or slats. Proper skirting saves money at the mill and produces better results. See our guide: How to Prepare Your First Fleece.
- Staple length
- The length of individual fiber locks, measured in inches. Different staple lengths require different processing approaches. Short staple (under 3 inches) cards well into batts. Long staple (4+ inches) is better suited for combing into top or carding into roving. Mills may ask about staple length to determine the best processing method.
T
- Top
- Combed fiber with all strands aligned parallel and short fibers removed. Produces smooth, strong, worsted-style yarn. Top is more processed than roving and costs more, but gives better stitch definition in the finished yarn.
- Turnaround time
- How long a mill takes from receiving your fiber to shipping back your finished product. Typically 6 to 16 weeks depending on the mill, season, and order complexity. Spring and early summer (post-shearing) is the busiest time. Always confirm turnaround before sending fiber.
V
- Vegetable matter (VM)
- Plant debris in raw fleece – hay, seeds, burrs, straw, bits of grass. Some VM is removed during washing and picking, but heavy contamination slows processing and can damage equipment. Mills may charge extra for high-VM fleece or refuse to process it. Skirting removes the worst of it.
W
- Woolen
- A style of yarn where fibers are oriented in multiple directions (not parallel). Made from carded batts using a long-draw spinning technique. Woolen yarn is lofty, warm, and light for its weight, with a soft halo. Less durable and less stitch definition than worsted. Ideal for sweaters, blankets, and shawls.
- Worsted
- A style of yarn where fibers are aligned parallel. Made from combed top or well-prepared roving using a short-draw spinning technique. Worsted yarn is smooth, strong, and shows stitch definition well. More durable than woolen. Ideal for socks, colorwork, cables, and high-wear items.
Y
- Yield
- The percentage of usable fiber remaining after processing. A raw fleece with 50 percent yield produces half its raw weight in clean, processed fiber. Yield depends on breed, condition, and how well the fleece was maintained on the animal. Typical yield: 40 to 70 percent for sheep wool, higher for already-clean fibers like alpaca.