Hair System Glossary

Welcome to the ReHair Learning Center!

Every article you’ll find here has been written with one goal in mind — to put control of your hair back into your hands. Whether you’re investigating the cause of your hair loss or looking for a solution for it, we have done our best to provide you with the information you are seeking. Simply search by keywords or phrases or choose category topics to explore so you can learn how to manage your hair loss or master the art of hair replacement right from the privacy of your own home.

If you ever have trouble finding the information you need, our hair replacement consultants are always available to answer your questions and guide you in the right direction.


The material that hairs are tied or injected into to create a hair system. Typically a knitted polyester lace, woven nylon monofilament, or solid-surface polyurethane.

Body chemistry

The chemical and hormonal makeup of one's body. Body chemistry impacts how well and how long hair system tapes and adhesives adhere to the scalp.

Color ring

An assortment of human hair swatches in various colors used to choose your overall hair color, as well as colors for highlights and lowlights.

Custom hair system

A hair system made to order, by hand, to a customer's exact size, shape, contour, hair length, density, and color specifications.


The act of (or final result of) cutting, styling, and blending a hair system to match a customer's chosen hairstyle and blend with their growing hair, if applicable.


The rough outer layer of a human hair follicle. It is mostly removed during processing, in order to reduce tangling.


The amount of hair ventilated in a hair system base. Refers to the overall thickness of the hair system (not individual hairs). Increasing density makes the hair system thicker; decreasing density makes it thinner.

Donor hair

Hair that is voluntarily donated by human beings to be used in making hair systems, wigs, and extensions.

Frontal hair system

A small hair system or topper designed to remediate only front-hairline-area thinning or recession.

Full cap hair system

A hair system that covers the entire head, such as is needed for alopecia totalis, alopecia universalis, or heavy overall diffused loss.

Hair System

A handmade scalp prosthetic designed to remedy hair loss. It mimics hair naturally growing out of one's head. A hair system is typically adhered to the scalp (not to growing hair) with specially formulated tape or liquid adhesive, and is generally removed and cleaned on a weekly or biweekly schedule. Also known as a hairpiece or toupee, hair systems are available for men, women, and children.

High Definition Hairline

The ReHair High Definition Hairline features soft, fine hairs starting at the front edge of the system that subtly increase back in thickness and density until it matches your full density, to replicate a naturally growing hairline.


A common mesh material used for hair system bases. It is typically a finely-knit polyester or nylon multifilament thread in a hexagon pattern, and allows natural scalp to show through the material, so the hair in the hair system looks like it is growing out of the scalp. It is very breathable, allowing water and sweat to pass through the material. Should not be worn over growing hair. Can accommodate a poly perimeter for easy cleanup if desired.

Learning curve

The period of time during which a hair wearer has to learn and practice the various procedures required for successfully wearing and maintaining a hair system.


A hair system base material made of a tightly woven monofilament nylon or polyester fiber that covers growing hair or scalp and mimics the look of scalp with hair growing out of it. Monofilament bases require a poly perimeter for structural stability. It is partially breathable and allows water to pass through.


The chemical process by which hair fades towards a reddish or yellow hue due to UV light (sun), chlorine-treated water, and/or hair-product exposure. Oxidation causes the microscopic outer layer of hair follicles to peel back, releasing green pigments and leaving behind red pigments, thus producing a reddish undertone.

Partial hair system

A hair system that typically only covers the top of one's head, such as is needed for pattern baldness. Can also be limited to smaller/other areas of the head.


The underside edge, roughly one inch deep, bordering the base of a hair system. Typically this is where the user places tape or liquid adhesive,or where a poly perimeter is applied.

Poly perimeter

A thin, pliable strip of polyurethane applied to the full or partial perimeter of a hair system. Adhesives are applied directly to the poly perimeter instead of the hair system base material. It is used to increase durability and simplify cleanup.


Recolor is the process by which blond hair is ventilated into the hair system base, then manually processed with darker color, so knots are completely invisible and the hair looks like it is naturally growing from your scalp.

Ready-to-wear hair system

Any hair system or wig that is pre-made and stored in a warehouse facility, ready to ship upon ordering. It is not a custom product. See “stock hair system.”

Reinforced sewing lines

In a full lace hair system with no poly perimeter, invisible “sewing lines” are sometimes stitched into the lace to give the base more shape, which allows for easier attachment and positioning.


Hand-tied hairs in lace and monofilament bases have a long end and a short end on either side of the knot. The short end is known as the return. For example, a 16-inch-long hair system might have a 4-inch return.


"Skin" is the industry term for a solid-surface polyurethane or silicone base material. There are different thicknesses of skin material, but at its lightest, it’s about as thick as a contact lens. It covers the natural scalp to create a faux scalp with hair growing out of it. It is gas permeable, but does not allow air, water or sweat to pass through.

Stock hair system

A hair system that is pre-made, by hand, to general specifications, stored in a warehouse facility, and ready to ship upon ordering. It is not a custom product, but can sometimes by customized to better suit the customer.


A temporary mold made from plastic wrap and tape which conforms to the exact shape and size of your head. From your template, the factory creates a more durable plaster mold, which is used to created the base of your hair system.


A hair system designed to cover, and/or enhance the density of, thinning hair on top of the head. Toppers cover only the top or part of the top of one's head. It is attached to one's growing hair by temporary means, such as hairpiece clips. It is designed to be removed on a daily basis.


The method in which hair is attached to the base of a hair system, including looped, hand-knotted or "injected" techniques. Ventilation also describes the direction in which hair is attached — or ventilated — into the base, such as brush back/forward, left/right part, etc.