WI Cosmetology key terms

The study of the structure of the human body and how its parts are arranged, including bones, muscles, nerves, and organs. Cosmetologists use this knowledge to work safely around sensitive areas.

The study of how the body's organs and systems function and interact, such as how skin, hair, and nails grow and how muscles move. It helps professionals understand client conditions and reactions to services.

A tube-shaped pocket in the skin from which a hair grows. It contains the hair root and is fed by blood vessels, and its shape helps determine whether hair grows straight, wavy, or curly.

A small cone-shaped structure at the base of each hair follicle that holds blood vessels and nerves. It supplies nutrients to the hair bulb and supports new hair growth.

An oil-producing gland attached to a hair follicle. It secretes sebum, which lubricates hair and skin, helps retain moisture, and contributes to scalp oiliness or dryness.

The pigment produced by cells called melanocytes that gives hair, skin, and eyes their color. Its type and amount determine whether color is blond, red, brown, or black.

A scale from 0 to 14 that measures how acidic or alkaline a substance is, with 7 being neutral. Hair and skin are mildly acidic, so products outside that range can affect them.

Harmful microorganisms that can cause disease or infection in humans. In the salon, they are controlled by proper cleaning, disinfection, and handwashing to prevent spreading to clients.

A process that uses chemical products to destroy most harmful microorganisms on tools and surfaces, except bacterial spores. It is required for implements that contact skin, hair, or nails.

Infection-control practices that treat all blood and body fluids as potentially infectious. They include handwashing, gloves, and proper handling and disposal of contaminated items for every client.

The middle and thickest layer of the hair shaft, made of elongated cells. It contains melanin and gives hair its strength, elasticity, and curl, and it is the layer changed by color and texture services.

The tough, clear outer layer of the hair shaft made of overlapping scales. It protects the cortex; when it is raised or damaged, hair loses moisture and shine and absorbs chemicals faster.

The ability of hair to absorb and hold moisture, related to how tightly the cuticle layers lie. Low porosity resists moisture, while high porosity absorbs quickly but loses moisture easily.

The ability of hair to stretch and return to its original length without breaking. Good elasticity indicates healthy, moisturized hair; poor elasticity means hair is weak and may break during services.

The angle at which hair is held away from the head while cutting. It controls how much length is removed and how the finished shape builds weight or layers.

The first section of hair cut in a haircut, used as a reference point for length. All other sections are cut to match it, keeping the haircut balanced and even.

A cutting technique that removes bulk, adds movement, or blends lines using tools such as shears, razors, or thinning shears. It changes how hair lies and how much volume it appears to have.

A chemical product, usually containing sodium hydroxide or another alkaline agent, that straightens curly or wavy hair by breaking bonds in the cortex. It requires careful timing and scalp protection.

A product used after a chemical texture service to stop the chemical action and rebuild hair bonds. It restores the hair's normal pH and helps the new shape hold.

A hydrogen peroxide solution mixed with hair color or lightener to start the color change. Its strength, measured in volume, determines how much lightness or deposit occurs.

A number from 1 to 10 that describes how light or dark a hair color is, with 1 being black and 10 being lightest blond. It helps match color formulas to the client's natural level.

A small test of a product, such as hair dye, applied to the skin before a service to check for an allergic reaction. Results are checked after 24 to 48 hours before proceeding.

Categories used to describe skin's oil and moisture balance, usually dry, oily, normal, and combination. Identifying the type guides product selection and service choices.

The removal of dead skin cells from the surface of the skin using mechanical or chemical methods. It can smooth texture and brighten the skin when done gently and appropriately.

The careful removal of blackheads and clogged material from pores during a facial, usually after softening the skin. It must be done gently to avoid injury or infection.

A light, gliding massage movement performed with the palms and fingers. It is used at the start of a facial to relax the client and apply product smoothly.

The visible, hard part of the nail that sits on the nail bed. It is made mainly of keratin and protects the tip of the finger or toe.

The area at the base of the nail where new nail cells are produced. Damage to it can cause ridges, thinning, or permanent changes in the nail plate.

The whitish, half-moon shape at the base of the nail plate. It is the visible part of the matrix and is usually lighter because the cells have not fully hardened yet.

The living skin at the base of the nail plate that overlaps the matrix area. It should never be cut during a manicure because it seals out infection.

A fungal infection of the nail that can cause thickening, discoloration, and separation from the nail bed. It is a disease, not a cosmetic problem, and should be referred to a physician.

A form that documents a client's service history, products used, preferences, allergies, and results. It supports communication, repeat services, and safe treatment decisions.

The amount added to the cost of a product or service to set its selling price. It must cover overhead and profit while staying competitive in the local market.

The specific group of clients a salon or stylist aims to serve, based on needs, location, income, or style preferences. It guides pricing, services, and marketing decisions.

The range of services and tasks a licensed professional is legally allowed to perform under state law. Performing work outside it can lead to discipline or loss of license.

The legal permission from a state board that allows a person to practice cosmetology after meeting education, testing, and application requirements. It must be kept current.

Required training hours that licensees complete to renew their license and stay current on safety, techniques, and laws. Requirements vary by state.

The federal agency that sets and enforces workplace safety rules, including hazard communication and bloodborne pathogen standards. Salons must follow these rules to protect workers.

A document from a product manufacturer that lists a product's hazards, safe handling, storage, and first-aid steps. It must be available to employees where chemicals are used.

Disease-causing microorganisms carried in blood or body fluids, such as hepatitis and HIV. Salons reduce risk with gloves, handwashing, and proper disinfection or disposal.