Mattress Terminology: Your A-Z Glossary to Understanding Mattress Lingo
Mattress spec sheets are full of jargon. This A-Z glossary explains the terms you will meet most often, so you can compare products fairly. Use it alongside our buying guide and guide to mattress types.
By the Sleep Comfort Insights editorial team at Essential Systems · Last reviewed
Mattress terms A to Z
A to C
| Term | Meaning |
|---|---|
| Adjustable base | A bed frame that raises the head or feet. See adjustable beds for back pain. |
| Bed-in-a-box | A mattress compressed and shipped in a box, usually foam or hybrid. |
| Bounce | How much the surface springs back when pressed. Latex and coils bounce more than memory foam. |
| Break-in period | The weeks a new mattress takes to loosen up and for your body to adapt. |
| Comfort layer | The upper layers of foam, latex or fiber that provide cushioning. |
| Contouring | How closely a surface conforms to body curves, typical of memory foam. |
| Coil count | The number of coils in a mattress; more is not automatically better. |
| Coil gauge | Thickness of coil wire. A lower gauge number means thicker, firmer wire. |
| Cooling cover | A fabric or treated cover meant to feel cool or wick heat; effects vary. |
D to H
| Term | Meaning |
|---|---|
| Density | Weight of foam per cubic foot. Higher density usually lasts longer. |
| Dunlop | A latex process that produces a slightly denser, firmer latex, often used in support cores. |
| Edge support | How firmly the perimeter holds up when you sit or lie near it. |
| Firmness | How hard or soft a mattress feels. See the firmness scale. |
| Foundation | A rigid, non-flexible support base, often slatted or boxed. |
| Gel foam | Foam infused with gel beads or swirls, often marketed for cooling. |
| High-density foam | Foam with heavier weight per cubic foot, often used for support layers. |
| Hybrid | A mattress combining a coil core with foam or latex layers. See hybrid mattresses. |
| Hypoallergenic | Designed to reduce common allergens; not a regulated guarantee. |
I to O
| Term | Meaning |
|---|---|
| ILD or IFD | Indentation load deflection or indentation force deflection, a measure of how much force is needed to compress foam. Higher numbers mean firmer foam. |
| Innerspring | A mattress with a coil support system and relatively thin padding. See innerspring mattresses. |
| Latex | Elastic foam from rubber tree sap (natural) or synthetic materials. See latex mattresses. |
| Loft | The thickness or height of a layer or pillow. |
| Memory foam | Viscoelastic foam that softens with warmth and slowly rebounds. See memory foam mattresses. |
| Motion isolation | How well a mattress prevents movement from traveling across the bed. |
| Off-gassing | A temporary smell from new foam or materials as compounds dissipate. |
| Open-cell foam | Foam with a structure that allows more airflow. |
P to S
| Term | Meaning |
|---|---|
| Pillow-top | An extra cushioning layer stitched onto the top of a mattress. |
| Pocketed coils | Individually wrapped coils that move independently, reducing motion transfer. |
| Polyfoam | Polyurethane foam, a common and lower-cost foam used in comfort and support layers. |
| Pressure relief | The ability to reduce concentrated pressure on shoulders, hips and other points. |
| Responsiveness | How quickly a surface adjusts when you move. |
| Sagging | Permanent loss of height or support, often measured in inches in warranty terms. |
| Sleep trial | A period in which you can test a mattress and return it. See warranties and return policies. |
| Spinal alignment | The spine keeping its natural curves while you lie down. See the science of spinal alignment. |
| Support core | The base of a mattress that bears most weight, whether coils or dense foam. |
T to Z
| Term | Meaning |
|---|---|
| Talalay | A latex process producing a lighter, more uniform, often softer feel than Dunlop. |
| Tempering | A way of describing how a material softens with body heat. |
| Thread count | Fabric weave density in sheets; it is rarely a meaningful mattress spec. |
| Tufting | Stitching or buttons that hold layers together. |
| Warranty | A written promise covering defects for a set period, usually with conditions. |
| Zoned support | Different firmness areas across the mattress, commonly firmer under hips and torso. |
Terms that sound technical but mean little
- Orthopedic: not a regulated term for mattresses, so it does not guarantee medical benefit.
- Medical grade: not a standard label; ask what it means.
- Cooling technology: ask what measurable feature provides the cooling.
- Luxury: marketing language without a defined specification.
What is a good coil count?
There is no universal number. Coil type, gauge and the comfort layers matter more than count alone.
What does ILD mean for me?
It tells you how firm a foam is. Compare ILD only between foams of similar type and thickness.
Is off-gassing harmful?
It is typically a temporary odor. If you are sensitive, air the room and look for independent emissions certifications.
What is the difference between Dunlop and Talalay?
They are two latex manufacturing methods. Dunlop tends to be denser and firmer; Talalay lighter and more uniform.