Glossary

The words, defined against a property

Every term here is defined by what it can be measured against — not by how it is described in a product listing. Where a maker's usage differs from common usage, the difference is noted.

Structure and construction

Pile height: The depth of the surface tufts, stated in millimetres. Read it with the measurement point in mind: pile is usually measured from the backing to the top of the tuft, and manufacturers differ on whether that is measured uncompressed or under load. A 10 mm figure from two makers is not always the same 10 mm.
Flatweave: Woven rather than tufted, so it has no pile at all. Crisp straight edges, reversible, thin enough to roll under, and the most forgiving construction in a hallway. It also shows every weave irregularity, because there is no tuft hiding the join.
Loop pile: Loops woven and left uncut. Harder to crush than cut pile, keeps a defined edge, and vacuums cleanly because the loops lie flat. The usual choice for stairs and busy doorways.
Cut pile: Tufts cut to length. Softer and denser underfoot than loop pile, but the tips are the first thing to abrade. A high cut-pile height in a hallway is a durability problem, not a comfort feature.
Back width: The width of the roll the rug was woven on, before cutting to size. When a rug is narrower than its roll, the pattern repeats across the floor and you can see it. Rugs sold at 9 ft 6 in wide need an 11 ft 4 in roll to avoid a visible repeat in an average room.
Knot density: Knots per square foot, stated by the maker. A rough indicator of how much material is fixed to the backing. It only compares fairly within one construction type — knot density on a flatweave and on a tufted rug are not the same measurement.

Materials

Face yarn: The visible surface fibre, distinct from the backing and from the foundation. Wool face yarn on a jute backing is a common construction; polypropylene face on a jute backing is another. The two behave completely differently in a wet room.
Jute: A bast fibre from the jute plant, used mostly for backing and for flatwoven rugs. Breathable and cheap, and it takes on water readily. In a bathroom or an uncovered basement it will smell within months.
Sisal: Harder and more water-resistant than jute, from the sisal plant. Still a natural fibre and still moisture-sensitive, but it tolerates more. Both are described as "jute" by careless retailers, which makes the distinction worth checking.
Polypropylene: A synthetic fibre that holds colour, resists staining, and can usually be machine washed. It does not shed, which is its main practical advantage. It also compresses more permanently than wool under furniture legs.
Cotton: Used in flatweaves and as a blend. Washable and keeps a sharp edge, but it pills at the surface over years and holds water longer than synthetics when it does get wet.

Curtains and window

Fullness: The ratio of fabric width to the width of the track or rod span. At 1× the fabric hangs flat and reads as a sheet. Most decorators work between 1.5× and 2.5×, and the higher end gives the fabric the depth that makes a curtain look expensive.
Drop: The finished length of the curtain, rod to hem. Distinct from the fabric drop, which is the length of the cloth before hemming. Sizing a curtain to the window rather than to the rod is the most common way a made-to-measure curtain ends up too short.
Light blocking: Stated as a percentage of light transmitted or blocked, which are two different numbers describing the same curtain. Manufacturers do not agree on the test method, so compare only within one brand when the figures conflict.
Blackout: Usually a three-layer construction with an opaque middle layer, though some blackout curtains are a single coated fabric. The coating is what blocks light and the coating is what makes the curtain stiff to fold and less washable.

Throws and cushions

GSM: Grams per square metre — the only thickness figure on a throw that transfers between makers. A 400 GSM throw is roughly twice the fabric of a 200 GSM one, and it feels roughly, not exactly, that much heavier.
Fill power: A measure of how much volume a given weight of down occupies, in cubic inches per ounce. Higher is better for the same weight, which means a warmer throw that weighs less. It applies to down and feather, and to no synthetic fill.
Loft: The thickness a cushion holds up after use. Foam loses loft faster than fibre, and down recovers if it is beaten and fluffed, which is why a down cushion that is reshaped nightly outlasts one that is never touched.