Mattress Glossary

Air bed: In the design of an air bed, chambers of air are used to provide support rather than coils and padding. This allows two sleepers to adjust each side of the bed to his or her comfort/firmness level.

Box spring: A box spring is a type of foundation designed to support the mattress. Consisting of a system of coils, made of thicker wire and larger than those generally used in mattress construction, it works much like a shock absorber does on a car, and is intended to distribute weight and cushion movement. Even though it might still look good as new, it is recommended that you get a new box spring whenever you buy a new mattress.

California King: The California king mattress, also called the western king, is 72” wide and 84” in length.

Coil count: The average full size mattress can have from 312 to 400 coils. Trying to compare the quality of a mattress based on coil count is difficult due to several varying factors in manufacturing processes such as spacing between coils, the size of coil used and the thickness of the wire. Coil count can vary from manufacturer to manufacturer.

Coil on Coil: Refers to coils are that are stacked on top of each other and is very durable. This type of coil system has the least motion transfer.

Coils: Coils insure the even distribution of your body weight throughout the length of the mattress. They can be configured in a variety of ways including sense and respond, hourglass and individual pockets.

Comfort: How comfortable you feel when sleeping, directly relates to the type of materials and the number of inches of padding used to make the top part of the mattress. The firmness of a mattress depends on personal preference and comfort level. For a good night’s sleep, the mattress should make you feel relaxed and comfortable while providing optimum support by cushioning you at contact points like the hip, shoulder, stomach or back.

Continuous Coil: It is a type of innerspring mattress coil configuration where each row of coils is made from a single piece of wire.

Convoluted foam: It is typically used as middle padding material in mattress construction. Also know as egg crate foam, the varying contours give it an overall softness while creating more surface comfort.

Corner guards: Made of plastic or metal, corner guards protect the fabric on the corner edges of the foundation from snagging on the bed frame.

Density: Density refers to the cubic weight of foam. While not directly related to the overall firmness of a foam mattress, it is an important indication of quality, which is directly connected to durability and support. The higher the density, the better the quality.

Edge support: The coil system of the mattress extends to the outer edges, providing additional support and “give” when someone sits on the edge of the bed. Edge support helps retain the overall shape of the mattress, prolonging its life.

Euro top: A euro top mattress provides additional layers of cushioning. Rather than adding it on top, the euro top incorporates extra wadding into the mattress itself. It can also look like a pillow top, but with the edges sewn down.

Fatigue: When a mattress displays signs of fatigue, it is time to replace the mattress. Symptoms of mattress fatigue include decreased resiliency (the shape of the sleeper remains for a period of time afterward), compression (height loss) and sagging.

Foam: Foams come in a variety of densities and qualities and serve different purposes in mattress construction. Polyurethane foam can be used as padding material in an innerspring mattress, as can convoluted foam. Visco (memory) and latex foams are used in both mattress construction materials and as padding for coils. Foams are also used as construction materials for mattress toppers.

Foundation: Intended as a base or support for the mattress, there are five main types of foundations: box spring, foam, posture box, semi-flex grid and modular grid. A good foundation will prolong the life a mattress.

Frame: Bed frames are typically made of metal but can be made of wood as well. They come in two heights, standard (7.25”) and low-profile (5.25”). For queen and king bed sizes, bed frames constructed of a heavy gauge steel are recommended. They should also have some kind of support system like a center bar or leg that will be able to handle the additional weight of larger-sized mattresses.

Full: A full mattress is 54” wide and 75” in length. It can also be called a double mattress.

ILD: Indentation Load Deflection or ILD is the measurement of how firm the foam is and how the surface feels when it is depressed. Although related, is not the same thing as density. ILD gauges the amount of force required to make an indentation in the foam. The more force needed, the more firm the foam is. ILD specifically relates to how comfortable the foam mattress feels when someone is lying on it.

High contour mattress: A mattress that measures 9 to 13 inches in thickness (or height) is a high contour mattress. One under 9 inches is referred to a standard mattress.

King: The standard king sized mattress is also known as the eastern king. The width is 76" and the length is 80”.

Latex Foam: A naturally derived foam made from rubber, latex foam is considered cushier and more pliable than other types of foam. For this reason, it is a popular material for foam mattresses. Latex is also anti-microbial and creates a naturally resistant environment for dust mites, mold and bacteria. It is bio-degradable. A mattress made of latex foam will conform to your body, reducing the impact of pressure points that can cause discomfort. It also reduces motion transfer that can disturb your sleep.

Memory Foam: Memory foam, also called Visco-elastic foam, is a temperature sensitive, slow recovery urethane foam that conforms to the body and distributes pressure according to body heat and weight. This man-made foam was originally developed for astronauts to provide comfort when in outer space. Like latex foam, memory foam reduces pressure points, motion transfer and the presence of allergens. Visco-elastic foam has an open cell structure that allows it to breathe, which is more conducive to sleeping comfortably. Memory foam mattresses are available in many thicknesses and densities, and like innerspring mattresses, come in different levels of softness and firmness. While it is used to make mattresses, memory foam is also used as material for pillow tops and as a padding component in the construction of innerspring mattresses.

Modular grid: A base made of square wire coils that absorbs weight and reduces sway. This type of foundation is also known as a torsion grid.

PBDE: PBDEs or polybrominated diphenyl ether are oragnobromine compounds commonly used in fabrics, furniture and electronics as a fire-retardant. Since 1998, when Swedish scientists noticed that substances related to PentaBDE were showing up in human breast milk, there have been concerns about the effects of exposure to PBDE. Many countries including several states in the US have banned or are in the process of phasing out the use of PBDE for the manufacture of household products. Many North American manufacturers have voluntarily discontinued its use. If PBDEs are used, it should be stated on the product or the manufacturer will be able to tell you if the flame-retardant was used on the mattress fabric.

Pillow top: A pillow top mattress resembles a quilted pad that is attached to the top of the mattress. This adds even more padding, giving it a feather pillow feel. Pillow tops can be made of a variety of materials, including natural fibers, foam and down.

Platform bed: A platform bed doesn’t require a box spring; the mattress sits directly on top of the bed box typically made of wood. The frame of the platform bed has slats that go from side to side, providing support to the mattress. Because it doesn’t use any type of foundation, a platform bed sits lower to the floor and is often referred to as a low-profile bed.

Pocket coils: A type of coil used in innerspring mattress construction. Cylindrical coils are enclosed in separate, flexible pockets that are then surrounded by foam or other types of cushioning material. Pocket coils are designed to reduce motion transfer across the surface of the mattress.

Pressure points: Typically affecting shoulders, hips and mid-calves, pressure points are where capillaries will close due to pressure. This can cause pins and needles, discomfort, stiffness or even pain. A mattress with “give” will cushion these areas of the body, relieving pressure.

Queen: A queen mattress is 60” wide and 80” long.

Quilting: The stitching used on the top of the mattress holding it in place is called quilting. The style of stitching and the number of stitches per square inch contributes to how firm or plush the mattress feels. The more stitching, the firmer it will feel. The type of stitching used to “fluff” up the fabric makes the mattress feel plush.

Recovery time: In addition to ILD, recovery time is the second most important factor in determining the comfort of a foam mattress. It refers to the length of time it takes for the foam to return to its original shape.

Resiliency: Resiliency is the mattress’s ability to return to its original shape after someone gets up from either sitting or sleeping on it.

Semi-flex: A type of foundation that is made up of a grid of wires designed to support the mattress.

Sleeping area: This refers to the amount of personal space a mattress gives each person. For example, the sleeping area for each person sharing a full mattress is 27 inches.

Tight top: A tight top mattress is one that doesn’t have a pillow top feature. Not to be confused with comfort level, a tight top mattress can still have a firm, plush or luxurious feel.

Ticking: Ticking is the fabric used to cover the mattress or the foundation.

Twin: A twin mattress, also known as a single, is 39” wide and 75” long.

X-long twin: X-long twin mattresses, also known as extra long single mattresses, are 39” wide and 80” long. They are less common than standard twin mattresses, and might be harder to purchase bedding for.