Glossary

26 words, and what each one is not saying

Bedding vocabulary is a mix of genuine technical terms, weave names, marketing phrases and certification programs, all set in the same font on the same listing. These are sorted the way they appear on the rest of the site rather than alphabetically, so related ideas sit next to each other. 26 of them link across to others.

Thread count: The number of threads in a square inch of woven fabric, counting warp and weft together. It stopped being a useful comparison once manufacturers began counting each ply in a multi-ply yarn as a separate thread, which can double a number without changing the cloth. It says nothing about fiber length, weave or durability, and nothing at all when the listing has not stated the fiber.; See alsoPercale Sateen Microfiber
Percale: A plain weave: one thread over, one thread under, evenly across. Nothing floats on the surface, which is why percale reads as matte and crisp rather than polished. It is a weave and not a quality grade, so any cotton woven that way can be sold under the word.; See alsoSateen Thread count Pilling
Sateen: A weave in which several threads float across the surface before being tied down, producing a faint sheen and a heavier, smoother hand. It is usually the warmer feeling of the two common cotton weaves. The floats are also what snags, and a pulled float does not go back.; See alsoPercale Satin weave Thread count
GSM: Grams per square meter, a measure of how much material is in a given area of fabric or fill. On a comforter it is the closest thing to an honest warmth specification, because it describes quantity rather than intent. Most listings leave it out and use a season word instead.; See alsoDown alternative Fill power Duvet insert
Fill power: A measure of how many cubic inches one ounce of down occupies when it has been allowed to loft, so higher numbers mean more insulation per unit weight. It applies to down and it does not transfer to polyester fills, which is why nothing in this catalog carries a fill power figure. Where a listing uses the term for a synthetic, it is borrowing a word from a different product.; See alsoDown alternative GSM Loft
Down alternative: Polyester fiberfill, named by comparison to a product it is not. Some of it is loose staple fiber and some is spun into clusters meant to behave a little more like down, and listings almost never say which. It holds warmth well and passes moisture poorly.; See alsoFill power GSM Gusset
Loft: How tall a pillow or a fill sits once weight is on it. There is no standard behind it, so a firm pillow from one seller and a firm pillow from another are not comparable. Adjustable fill sidesteps the problem entirely by letting the owner set the height.; See alsoGusset Memory foam Down alternative
Gusset: A strip of fabric sewn around the perimeter of a pillow so it has a wall instead of a slope. It lets a fill keep a squarer shape under load and it holds height longer than a plain bag construction. It does not stop fill from felting eventually.; See alsoLoft Down alternative Pilling
Pocket depth: The distance from the top corner seam of a fitted sheet down to where the elastic gathers. It is the number that decides whether a sheet stays on, and it has to cover the mattress, plus anything on top of the mattress, plus enough left to turn under. Manufacturers do not all measure it the same way.; See alsoDeep pocket Elastic all-around Memory foam
Deep pocket: A marketing phrase for a fitted sheet cut taller than average, with no fixed threshold behind it. One seller deep pocket may be 14 inches and another 18. It is only useful when an inch figure is stated next to it.; See alsoPocket depth Elastic all-around
Elastic all-around: Elastic run through the entire hem of a fitted sheet rather than gathered only at the four corners. It grips a range of mattress heights instead of one, which is what keeps a deep pocket from riding up on a shallow mattress. It is a construction fact and worth looking for in a listing.; See alsoPocket depth Deep pocket
Microfiber: Polyester extruded as filaments fine enough that the fabric behaves differently from ordinary polyester cloth. It describes the fineness of the fiber rather than naming the polymer, so under the textile labeling rules it is not a generic fiber name. Most bedding microfiber is then brushed to raise a soft nap.; See alsoPilling Thread count Hypoallergenic
Rayon and viscose from bamboo: Regenerated cellulose fiber made by chemically dissolving bamboo and extruding it, which is the same process that turns wood pulp into rayon. The finished fiber is rayon, and the FTC requires it to be labeled that way with bamboo named only as the source. It is at its weakest when wet.; See alsoTPU laminate GOTS Pilling
Satin weave: A structure in which long floats run across the surface with very few tie-down points, giving the highest shine of any common weave. It names a weave and never a fiber, so satin bedding may be polyester, nylon or silk, and a listing saying satin has not stated its content. The floats snag easily and a pull is permanent.; See alsoSateen Percale Thread count
Memory foam: Polyurethane foam modified to be viscoelastic, so it deforms slowly under load and returns slowly when the load comes off. That delay is the entire product. It appears here as slabs cut for toppers and as shredded fill packed into pillows, and neither form is machine washable.; See alsoGel infusion CertiPUR-US Loft
Gel infusion: A gel phase mixed into foam before it cures, usually visible as beads or a color through the slab. It is a real manufacturing step rather than pure marketing, and no listing in this catalog attaches a unit or a measurement to it. What it does not do is turn a foam block into a fabric.; See alsoMemory foam CertiPUR-US
CertiPUR-US: A certification program for flexible polyurethane foam, covering what the foam is made without, including certain flame retardants, heavy metals and phthalates, plus a limit on volatile organic compound emissions. It applies to the foam and not to the cover or the finished item. It is not a comfort rating, a durability rating, or a statement that a product suits any particular person.; See alsoMemory foam GREENGUARD Gold OEKO-TEX
OEKO-TEX: A family of textile certifications, of which Standard 100 is the one that appears most on these listings. It tests a finished article against limits for regulated and restricted substances, set according to how close the article sits to skin. It says nothing about durability, fiber content accuracy or performance.; See alsoGOTS CertiPUR-US GREENGUARD Gold
GOTS: The Global Organic Textile Standard, a privately administered supply-chain standard covering organic fiber content along with processing, chemical inputs and social criteria. It is run by a non-governmental body rather than by a US agency, and in the United States what the word organic can legally claim is governed separately by USDA rules. It is a farming and processing standard, not a performance one.; See alsoOEKO-TEX Rayon and viscose from bamboo
GREENGUARD Gold: A chemical emissions certification: the product has been tested against limits for what it releases into indoor air, with Gold as the stricter tier. Emissions testing is not a health outcome and not a quality grade. It appears on one foam pillow in this catalog.; See alsoCertiPUR-US OEKO-TEX Hypoallergenic
Hypoallergenic: A word with no federal definition governing its use on bedding. FDA has stated that for cosmetics there are no standards or definitions behind it, and no agency defines it for textiles either. It appears on this site only inside a description of what a listing says.; See alsoOEKO-TEX GREENGUARD Gold Microfiber
TPU laminate: Thermoplastic polyurethane bonded as a thin film to the back of a protector face fabric, which is what makes the protector waterproof. It is the component that fails, and it fails to heat rather than to wear. Dryer temperatures above what it was built for make it stiff, then brittle, then cracked.; See alsoPocket depth Rayon and viscose from bamboo
Bed in a bag: A comforter shipped together with sheets, pillowcases and usually shams, sold as one purchase. It is convenient and it means every piece ages on the same schedule whether that suits you or not. Eight of the twelve comforter listings here are sold this way.; See alsoDuvet insert Corner ties GSM
Duvet insert: A comforter used inside a removable cover rather than as the visible top layer. Running one this way is the single change that most extends how long the comforter itself goes between washes, since the cover takes the wear. A comforter needs corner ties to work properly as an insert.; See alsoCorner ties Bed in a bag GSM
Corner ties: Fabric loops sewn at the corners of a comforter so it can be anchored inside a duvet cover. Without them the comforter slides and collects in a lump at one end. They can be resewn if they tear out, which is one of the few home repairs worth doing on bedding.; See alsoDuvet insert Bed in a bag
Pilling: Short fibers working loose from the surface and balling up where the fabric is rubbed, which is why it appears first where a forearm or a heel rests. Short staple cotton and brushed polyester both do it readily. Once it starts, washing accelerates it, and there is no reversing it.; See alsoMicrofiber Percale Sateen

Fuller treatments of the fabrics and fills are on Materials, and the certification marks get a column each explaining what they leave out. The measurements are worked through on Sizes and Pocket Check.