The Complete Mattress Glossary & Guide of 2019

Mattress Glossary

Have you ever wondered about some of the technical terms used in the world of mattresses?

Substances that cause allergic reactions in some individuals. Foam that is mildew and dust-resistant can be a good choice for allergy sufferers.

A chamber used to obstruct the movement of a substance (for example, water).

Bed Frame
A bed frame that maintains the position of the foundation, headboard, and footboard

bed frame

Bed Support
The bed rails and frame that help prevent the set from warping, twisting and sagging.

Body Alignment
The relational positioning and balance of the spine, muscles, and joints.

Border Wires
The heavier-gauge wire that keeps the mattresses shape and increases its durability.

Box Spring
A foundation is made of cone-shaped wire coils.

Box Spring

A spring to provide resistance to applied weight.

Coil Configuration
The arrangement of coils in a specific pattern.

Comfort Zone
The layers of upholstery between the support system and the ticking of the mattress.

Continuous Coil
A mattress construction in which a single wire is formed into a row of coils. Also integrated coil.

Corner Guard
Made of plastic, its purpose is to protect the corners of the foundation.

Edge Guards
Heavy-gauge wires at the mattress edges that help prevent sagging at the edges. They can also increase the usable sleeping surface and maintain structural integrity.

A term to describe how much resistance the mattress applies to body weight and the resulting “feel”.

The bottom component of the sleep set that transfers and distributes the weight of the mattress.

The structural system that supports a sleep set, often including the headboard, footboard, and rails.

A small helix or spiral-shaped wire that is used to connect coils.

A term to describe objects that have a decreased likelihood of provoking an allergic reaction.

Innerspring Mattress
A mattress with wire coils as its support system.

Innerspring Mattresses

Independent Coil
An innerspring mattress construction that uses individually wrapped coils. Coils move independently of each other, so if your partner moves, you are less likely to be disturbed. Also called pocket-coil.

Integrated Coil
A coil system that distributes your body weight evenly across an innerspring mattress, supporting and cushioning the shoulders, back, hips and legs.

Modular Coil/Modular Grid
Also known as a torsion grid, this refers to a square wire coil used in foundations to absorb weight and reduce lateral sway.

Offset Coil
A wire coil similar to an open coil, but with squared ends.

Open Coil
This is an hourglass-shaped wire coil.

Pillow top
The semi-attached layer at the top of a mattress that provides additional softness and support.

Pillow top mattress

A cylindrical wire coil that is wrapped in its own cloth sleeve.

Posture Box
A foundation that has no wire coil support system. It is made entirely of wood.

Pressure points
Points on the body that bears the most weight and pressure when lying down; common pressure points are the shoulders, hips, and knees.

A foundation with a grid of wires that firmly supports a mattress.

Sleep Set
A general term to describe the combination of foundation, mattress, headboard, footboard and bed frame.

Support is referred to in several ways:

  • The support system of a mattress, such as coils or foam
  • The structure that supports the sleep set, such as a bed frame
  • The foundation of a sleep set that supports the mattress
  • The level of firmness provided to the user

Support System
The basic supporting structure of the mattress. This structure could consist of various types of wire coils, foam, water or air.

The fabric covering a mattress or foundation.

Upholstery Layers
The foam, padding, and fibers used between the support system and ticking of a mattress to provide cushioning and comfort.

Foundation Types

Posture Box

Posture Box Foundation bedThe posture box is a wooden frame with a flat top, covered with the same ticking as the mattress. This type of construction is usually the least expensive, made of pine or similar hardwood, covered with some type of particleboard. The posture box has no springs and does not work well to absorb the weight from the mattress. A mattress on a posture box will most likely have a shorter lifespan.

Semi-Flex Grid

The semi-flex grid is a wooden frame with a rigid metal wire grid attached above 7 or 8 supporting slats. The semi-flex grid is firm and minimizes flex to support the mattress.


The foam foundation is made of high-density foam and is used to support foam mattresses. This foundation provides an even distribution of weight from the mattress, helping prolong the mattress life, check the Dreamfoam memory foam mattress reviews on foam globes to learn more.

Coil Spring or Box Spring

Box Spring FoundationThis foundation features a heavy-duty spring coil system to support the mattress. If the springs match the mattress it is called a coil upon coil box spring. The coils are made of a heavy-gauge wire to help absorb impact on the mattress. The coil spring foundation provides good support and a softer feel than the more basic foundations but research has shown that boxsprings move too much and cause some innerspring mattresses to sag prematurely. Most mattress manufacturers have switched to a rigid foundation (see Modular Grid below) making mattresses last longer. For more information on coils and gauges, see Coils and Gauges.

Grid Foundations

The modular grid or grid foundation is considered by many to be the best support for a mattress and is used in the best quality sleep sets. Heavy-gauge square coils are attached to a wood frame, which tends to have more slats than less expensive foundations. The square coils evenly absorb the torsion of the weight transferred to them and help prolong the life of the mattress effectively.

Bed Frames

Bed FramesWhat type of support does a sleep set need? This is an important factor for larger bedding where improper support can result in twisting or sagging of the sleep set. The side rails of a bed frame provide adequate support for twin and double-size sleep sets but queen-size or king-size sleep sets require some extra support. Select a frame that has a center support rail with extra legs – six are preferable to the standard four. Make sure you understand the correct support required for your mattress set because inadequate support may invalidate your warranty.

Mattress Sizes

This section of the website will provide you with information about standard mattress sizes. Not sure what size mattress you need? Consult our mattress size diagram and chart.

mattress sizes

10 Things You Need to Know Before Buying a Mattress

1. NEGOTIATE. You can – and should – negotiate price on almost all mattresses. Most major mattress brands (except Tempur-pedic) have negotiable pricing and you will find it worth your while to haggle with the salesman. At the least, you should be able to get your salesperson to throw in some free pillows and/or sheets.

2. WARRANTY. Most mattresses come with a 10-year warranty. However, this warranty is void if the mattress has even the slightest stain on it. If you want to have a hope of using your mattress warranty at some point it is critical that you purchase a waterproof mattress cover. Some warranties also require that the bed be flipped every six months so ask your salesman about all of the details.

moving mattress3. TAKE YOUR TIME! Don’t rush through the purchasing process. There are many different types of mattresses (innerspring, memory foam, air, water, futon) and even more manufacturers (Sealy, Serta, Simmons, Tempur-Pedic, King Koil, Spring Air, etc.). Don’t just lie down on a mattress for 10 seconds; take your time and relax on it, then try another. If you sleep with a partner be sure you bring that person with you to test. Lie on the bed facing away from your partner and see if you can figure out when he/she is getting in and out of bed.

4. FIRMNESS. Firmer is not necessarily better. There is a common sentiment that a firm bed is good for the spine. In fact, this is not the case. A very firm mattress doesn’t “give” which can force your spine to bend at the hips and shoulders. A softer (plusher) mattress can allow your hips and shoulders to sink into the bed slightly, keeping your spine straight when you sleep on your side. Don’t confuse firmness with supportive – they’re two different things. Like Goldilox, sometimes it’s best to pick the mattress that is not too firm and not too soft (plus) but somewhere in the middle: just right.

5. SIZE. Pick the right size for your height. If you’re a tall person (over 6 feet) you will probably want to go with a king-size bed. If you’re extremely tall you will want to consider the California king size. The California king is slightly narrower and taller than the “regular” California mattress. For most couples under six feet tall, a queen size bed should provide enough space to sleep comfortably. For spare rooms or for kids rooms, consider a mattress or a space-saving daybed used for seating and sleeping. These beds usually offer a trundle which can double as a storage drawer or when paired with a mattress can be used for additional sleeping capacity.

6. COILS. More coils are not necessarily better. As most salesmen will tell you when you first start shopping, the two main types of innerspring mattresses are an interlocking coil and independent coil. Interlocking coil mattresses actually require fewer coils because the coils are tied together with wire. Independent coil mattresses require more coils because each one must work on its own to support you. The benefit of an independent coil mattress is that it is less prone to movement if your partner is getting in and out of bed. This can be an important factor to consider if you’re a light sleeper.

7. HYBRIDS. Sometimes a hybrid mattress is worth considering. The lines between the different types of mattresses have blurred in recent years with the advent of innerspring mattresses with memory foam, innerspring futon mattresses, and innerspring mattresses that have water chambers inside them. Don’t get sold on too much hype – the ultimate test is how it feels to you.hybrid mattress

8. BUDGET. Decide on a budget before you go into the store. Mattresses are very expensive – it will typically cost you at least $800 for a decent mattress & box spring combo and many people spend $2,000 or more on a bed. As you test different mattresses you will undoubtedly notice that the more expensive the mattress, the more comfortable it feels. Mattress salesmen love to use the “this will last you ten years so it will really only cost you fifty cents a night to sleep on this $3,000 mattress”. While that’s technically true, if you don’t finance it through the mattress store or a credit card, you have to pay that entire fee before you sleep on it for one night! If you set a budget before you go in of, say, $1200, look at mattresses up to the $1600 range and then bargain for your price. If the salesperson won’t take your offer go somewhere else. Sometimes if they see you physically heading for the door, $1200 will sound a lot better than no sale.

9. BRAND. Sometimes it’s worth it to go with a major brand. Smaller mattress retailers will sometimes try to sell you on a mattress that they claim is “just as good” as a major brand but at a much lower price. As with most things, you get what you pay for. Inexpensive mattresses are often cheaper because corners have been cut somewhere in the manufacturing process whether it’s the coils, the foam, the cotton batting, or the actual construction of the mattress itself. If you can afford it, you’ll likely get more miles out of a name brand mattress. Don’t be afraid to push your salesman! Negotiating is uncomfortable and difficult for many people but it helps to know what you want and what you want to pay for it before you go in. Don’t hold back when asking your salesperson hard questions about warranties, delivery fees, construction, and hidden charges. You’ll be much happier you asked the questions upfront rather than getting burned when you see the bill or getting denied on a warranty claim. If you’re going to spend $1,000 be sure you don’t get taken for a ride. More tips to help you choose a mattress here.

10. DON’T COUNT ON A PILLOW TOP. Some customers assume that they can “fix” a cheaper mattress by throwing a pillow top on it.  This may sound like a good idea but, particularly for innerspring mattresses, if you don’t have good support underneath the pillow top will just follow the curve of the bed. In short, a sagging mattress can’t be repaired with a pillow top.  Keep in mind that a euro top is simply a pillow top that’s been permanently sewn to the top of the mattress.