Confused by mattress lingo? You’re not alone. From firmness levels and fill types to certifications and safety standards, mattress shopping can get overwhelming, and fast. 

That’s why we created this glossary. Whether you're comparing materials, sorting through certifications or just wondering what “encased coils” even are, this guide will help you decode the fine print and shop with confidence.

Mattresses come with more than just layers – they come with labels, claims and buzzwords. Some are helpful. Others? Not so much. This glossary breaks down the most important terms you’ll see while shopping, especially if you're looking for a healthier, more sustainable option.

Mattresses come in many forms, and understanding the differences can help you narrow down what truly works for your body, lifestyle and values. 

Here’s a breakdown of the most common types you’ll encounter while shopping:

Innerspring: A traditional mattress made with a network of metal coils that provide support and bounce.

Latex: A durable, responsive material made from rubber tree sap (natural latex) or synthetic chemicals (synthetic latex).

Hybrid: A mattress that combines a coil support system with layers of latex or foam for comfort. Hybrid mattresses are designed to offer the best of both worlds: sturdy support from springs and pressure relief from the top layers.

Memory Foam: Memory foam is a subtype of polyurethane foam known for its slow-sinking, body-hugging feel. While some brands market these mattresses as “contouring,” many contain petrochemicals and may off-gas VOCs.

Organic Mattress: A mattress made with certified organic materials like organic latex, wool, and cotton. These mattresses are also produced in certified facilities and avoid toxic chemical treatments.

Mattress-in-a-Box: A mattress that’s compressed, rolled, and shipped directly to your door in a compact box.

Cooling: A catch-all term used to describe materials or constructions that help regulate temperature.

Finding the right comfort and support balance is key to waking up refreshed – not achy. 

These terms describe how a mattress feels and how well it supports your body throughout the night:

Firmness Scale: Usually rated from 1 (ultra-soft) to 10 (extra-firm), the firmness scale gives a general sense of how soft or firm a mattress feels.

Contouring: How well a mattress molds to the shape of your body. Contouring helps relieve pressure points, especially at the shoulders, hips, and lower back.

Pressure Relief: The ability of a mattress to reduce pressure on key areas of the body, like hips, shoulders, and joints.

Motion Isolation: How well a mattress prevents movement on one side from being felt on the other. A helpful feature for couples!

Responsiveness: A responsive mattress quickly adjusts to your movements, rather than leaving you “stuck” in one spot.

Edge Support: This refers to how well the edges of a mattress hold up under weight. Good edge support makes it easier to sit or sleep near the edge without feeling like you’ll roll off.

Zoned Support: A mattress design that provides varying levels of firmness or support across different areas (e.g., firmer under the hips, softer under the shoulders).

Breathability: How well air flows through a mattress. Breathable mattresses help prevent overheating by allowing heat and moisture to dissipate.

What your mattress is made of matters, especially when it comes to comfort, safety and sustainability. 

Here’s a closer look at some of the most common (and most confusing) materials used in mattresses today:

Organic Cotton: Cotton grown without synthetic pesticides, herbicides, or GMOs. GOTS-certified organic cotton also ensures socially responsible manufacturing.

Organic Wool: Wool sourced from sheep raised according to organic farming standards, without synthetic treatments. In mattresses, organic wool helps with temperature regulation and acts as a natural flame barrier.

Organic Latex: Latex made from rubber tree sap and certified to the GOLS standard. It’s breathable, durable, and contouring, without the petrochemicals or off-gassing associated with synthetic latex or foam.

Polyurethane Foam: A petroleum-derived material used in many conventional mattresses. Often includes chemical flame retardants and may emit VOCs.

VOCs (Volatile Organic Compounds): Gases released from certain synthetic materials, including foams and adhesives. Some VOCs can contribute to indoor air pollution or health concerns.

Flame Retardants: Chemicals added to some mattresses to meet flammability regulations. Many chemical flame retardants are linked to health risks and environmental harm.

Synthetic Fill: Man-made fibers (usually polyester) used for softness or bulk. While inexpensive, these fills don’t breathe as well and may contribute to off-gassing.

Adhesives/Glues: Often used to bond mattress layers together. Conventional adhesives may contain VOCs or toxic solvents.

Fiberglass: A material sometimes used as an internal fire barrier, especially in low-cost foam mattresses. If the cover is removed or damaged, fiberglass can become airborne and cause irritation.

GMOs (Genetically Modified Organisms): Often used in conventional cotton farming, genetically modified organisms are organisms whose genetic material has been altered using biotechnology.

Phthalates: A group of chemicals used to make plastics more flexible, often found in waterproof layers or vinyl surfaces. Some phthalates are linked to hormone disruption and developmental issues.

Synthetic Latex: A man-made version of latex derived from petrochemicals, not rubber trees. It mimics the feel of natural latex but lacks its breathability, durability, and eco benefits.

Off-Gassing: The release of chemical odors from synthetic materials, especially memory foam and conventional adhesives. While some off-gassing is harmless, others may affect air quality.

Beyond materials and firmness, how a mattress is built plays a big role in how it performs.

These are the behind-the-scenes components that determine durability, comfort and overall sleep experience:

Comfort Layer: The top layer(s) of a mattress designed to provide cushioning and pressure relief.

Support: The core structure that keeps your body aligned and supported throughout the night.

Quilt: The topmost surface layer, often stitched for texture and comfort.

Encased Coils (or Pocket Coils): Individually wrapped springs that respond independently to pressure. They help reduce motion transfer and provide targeted support.

Coil Gauge: The thickness of the wire used in coil springs. A lower number means a thicker, firmer coil. While not always listed in product specs, coil gauge can influence how supportive or soft a mattress feels.

Coil Count: The total number of coils in a mattress. While more coils can improve support and contouring, coil quality and design also matter.

Pillow Top: An extra layer of padding sewn to the top of a mattress for added softness. This effect can also be mimicked by adding a mattress topper.

Mattress Encasement: The cover that surrounds the entire mattress to protect it from allergens, moisture, or pests. (Not to be confused with a fitted protector!)

When it comes to mattresses, certifications help separate greenwashing from genuine standards. 

These third-party seals give you peace of mind that what's inside your mattress is truly healthier and more sustainable:

GOTS (Global Organic Textile Standard): The leading certification for organic textiles like cotton and wool. GOTS covers everything from farming to manufacturing to ensure the materials are truly organic and produced responsibly.

GOLS (Global Organic Latex Standard): Applies specifically to latex made from rubber tree sap. GOLS ensures the latex is organically sourced and processed in facilities that meet strict environmental and social criteria.

GREENGUARD Gold: A certification for low chemical emissions. Products with this label have been tested to meet strict limits for VOCs, helping protect indoor air quality.

EWG Verified®: A certification from the Environmental Working Group that screens for harmful chemicals based on the latest scientific research.

MADE SAFE®: This certification evaluates materials for known or suspected toxins and bans thousands of harmful substances. It’s one of the most rigorous standards for safer products.

FSC® (Forest Stewardship Council): Certifies that wood and paper products come from responsibly managed forests.

1% for the Planet®: A global movement of businesses that donate 1% of annual sales to environmental causes.

USDA Organic: The official seal for certified organic agricultural products in the U.S. While this label doesn’t apply to finished mattresses, it may appear on raw materials like cotton used within GOTS-certified products.

From finding the right fit to understanding what your purchase includes, these terms will help you navigate the final stages of mattress shopping with confidence.

Twin: A standard mattress size measuring approximately 38" x 75". Ideal for kids, bunk beds, or smaller spaces.

Twin XL: Like a twin, but 5 inches longer: 38" x 80". Common in college dorms or for taller sleepers who need extra legroom.

Full: Also known as a double, this size measures about 54" x 75". Wider than a twin but still a tight fit for two adults.

Queen: One of the most popular mattress sizes, measuring 60" x 80". Offers a comfortable balance of space and size for couples or solo sleepers who like to stretch out.

King: A spacious option measuring 76" x 80". Great for couples or families who co-sleep or share the bed with pets or kids.

Cal King: Slightly narrower but longer than a standard king: 72" x 84". A good option for taller sleepers or long, narrow rooms.

Sleep Trial: A set period (often 100+ nights) to try a mattress at home and return it if it’s not the right fit.

Warranty: A guarantee covering defects in materials or craftsmanship for a specific period.

Now that you know the terms, here’s the trick: don’t just look at what a brand says, look at what they show. Transparent sourcing, legitimate third-party certifications and a full materials disclosure are better indicators of quality than vague promises like “eco-friendly” or “natural.”

Because when you know what you’re really sleeping on, you sleep better.