OR Cosmetology key terms

The process of significantly reducing the number of disease-causing microorganisms on surfaces and tools by cleaning and then applying an EPA-registered disinfectant. It is a lower level of protection than sterilization and does not necessarily destroy bacterial spores.

The use of an EPA-registered product, in the correct dilution and contact time, to destroy or inhibit most pathogenic organisms on nonporous implements and surfaces. It does not reliably kill all spores and is required for items that contact skin or blood.

The complete destruction of all microbial life, including bacterial spores, usually achieved with an autoclave using steam under pressure. It is the highest level of decontamination and is reserved for items that may enter tissue or contact broken skin.

A device that sterilizes metal implements with high-pressure steam, typically at about 250 degrees Fahrenheit for a set time. Items must be cleaned and dried first, and the unit must be tested regularly, often with a spore strip, to confirm effectiveness.

A standard approach in which every client is treated as potentially infectious and barrier protection such as gloves is used for all services where blood or body fluids could be contacted. The principle removes the need to guess who may carry a pathogen.

Microorganisms present in blood that can cause disease, notably hepatitis B, hepatitis C, and HIV. Cosmetologists must follow exposure-control rules, use gloves, and properly dispose of contaminated sharps and materials to prevent transmission.

A standardized document supplied with a chemical product that lists its hazards, safe handling and storage requirements, first-aid measures, and disposal guidance. Cosmetologists must keep these sheets accessible for every hazardous product in the salon.

The set of practices for storing, mixing, and using salon chemicals safely, including labeling containers, avoiding incompatible products, and ensuring ventilation. It protects both workers and clients from burns, fumes, and accidental exposure.

The design and adjustment of tools, chairs, and work habits to fit the body and reduce strain. In cosmetology it includes proper chair height, wrist position, and posture to prevent repetitive-motion injuries and back pain.

A scale from 0 to 14 measuring acidity and alkalinity, with 7 neutral. Hair and skin are mildly acidic near 4.5 to 5.5; products above or below this range can swell or tighten the cuticle and affect color and texture results.

Describes a product formulated near the natural pH of hair and skin, roughly 4.5 to 5.5. Such products minimize cuticle swelling and are used for shampoos, conditioners, and after-color treatments to preserve moisture and shine.

A solution with a pH above 7. Alkaline products open the hair cuticle, which allows color and wave solutions to penetrate but can leave hair dry or rough if not followed by an acidic treatment.

The structure of skin in layers: the epidermis on the surface, the dermis beneath containing nerves and blood vessels, and the subcutaneous layer of fat. Understanding these layers guides safe waxing, massage, and product application.

The outermost, thinnest layer of skin, made of cells that continually renew and contain melanin-producing melanocytes. It forms the barrier that protects underlying tissue and is the layer most affected by exfoliation and surface treatments.

The thicker middle layer of skin containing collagen, elastin, hair follicles, glands, and blood vessels. It supports the epidermis, and damage reaching this layer can cause scarring, so treatments must respect its depth.

The pigment produced by melanocytes that gives skin, hair, and eyes their color and provides some protection from ultraviolet radiation. Its amount and type influence color results and the risk of chemical irritation.

The repeating phases of hair growth: anagen, when hair actively grows; catagen, a short transition; and telogen, a resting phase before shedding. Understanding the cycle explains why waxing and laser results vary between clients.

The active growth stage of the hair cycle, lasting years and determining how long a hair can grow. Because the follicle is actively producing hair, this phase matters for chemical services and for hair removal timing.

The resting stage of the hair cycle, when growth stops and the hair is eventually shed. Hairs in this phase are often the ones released during brushing or waxing, which is why scheduling matters for smooth results.

The tough, transparent outer layer of the hair shaft made of overlapping scales. Its condition controls shine, moisture retention, and how evenly color or wave solutions penetrate, so it is central to every chemical service.

The middle layer of the hair shaft, containing the bulk of the fiber and the melanin that gives hair color. Chemical changes such as coloring, perming, and relaxing occur primarily in this layer, which also provides strength and elasticity.

The innermost core of the hair shaft, composed of loosely arranged cells and often absent in fine or light-colored hair. It contributes little to strength or color and is mainly of anatomical interest.

The ability of hair to absorb and retain moisture, determined by the condition of the cuticle. Low-porosity hair resists moisture, while high-porosity hair absorbs quickly but loses it fast, affecting color and treatment choices.

The ability of hair to stretch and return to its original length without breaking. Good elasticity indicates healthy, well-moisturized hair; poor elasticity signals damage and warns against strong chemical services.

The process of changing hair pigment using temporary, semipermanent, or permanent color products. Permanent color uses developer to lift natural pigment and deposit new color within the cortex, requiring an understanding of level and tone.

A hydrogen peroxide solution that, when mixed with hair color or lightener, opens the cuticle and oxidizes pigment to lift or deposit color. Its volume strength determines the amount of lift and must be matched to the product and desired result.

A strong alkaline chemical product, usually containing sodium hydroxide or a no-lye alternative, that straightens curly hair by breaking disulfide bonds in the cortex. It requires careful strand testing, timing, and neutralizing to avoid damage.

A product applied after a relaxer or permanent wave to stop the chemical action and rebuild disulfide bonds in the new shape. Proper neutralizing restores the hair's strength and prevents the service from continuing to process.

A chemical service that uses a reducing solution to break disulfide bonds and a neutralizer to reform them around a rod, creating lasting curl. Rod size, processing time, and hair condition determine the final pattern.

A professional skin service including cleansing, exfoliation, massage, and masking to improve the appearance and condition of the face. It requires skin analysis, sanitation, and knowledge of product types suited to the client's skin.

A cosmetic service for the hands and nails that includes shaping, cuticle care, massage, and polish. It requires sanitation of implements, knowledge of nail structure, and care to avoid injuring the surrounding tissue.

A professional service for the feet and toenails involving soaking, exfoliation, nail shaping, and polish. It demands strict sanitation, careful handling of calluses, and awareness of conditions such as fungal infection that require referral.

The visible, hard keratin structure covering the tip of each finger or toe. Its health reflects nutrition and care, and understanding its structure helps the cosmetologist avoid over-filing and recognize signs of disorder.

A structured conversation before a service in which the cosmetologist assesses the client's hair, skin, or nails, discusses goals, reviews allergies and history, and explains the plan. It protects both parties and guides realistic expectations.

The visual and tactile assessment of a client's skin to determine its type, condition, and sensitivities before a facial or waxing service. Findings guide product selection and identify conditions that should be referred to a physician.

The use of towels, capes, and neck strips to protect the client's clothing and skin and to maintain a professional, sanitary environment during a service. Proper draping also supports modesty and comfort.