NE Cosmetology key terms

A 0-to-14 scale measuring hydrogen ion concentration; 7 is neutral, below 7 is acidic, above 7 is alkaline. Hair and skin prefer slightly acidic products, and pH affects swelling of the hair shaft and the action of chemical services.

A shampoo formulated near the natural pH of hair and scalp, roughly 4.5 to 5.5. It minimizes cuticle swelling and color fading, making it suitable for daily use and for clients with chemically treated or color-treated hair.

A liquid with a pH above 7 that swells and opens the hair cuticle. Alkaline products allow penetration of color and waving chemicals but leave hair rougher, so they are followed by an acidic conditioner to restore the cuticle.

The outermost layer of the hair, made of overlapping, scale-like cells that protect the inner layers. Its condition determines shine, porosity, and resistance to chemical penetration; rough or lifted cuticles make hair dull and prone to breakage.

The middle and thickest layer of the hair shaft, composed of elongated cells containing melanin and the protein bonds that give hair strength and elasticity. Chemical services such as coloring and permanent waving act primarily in this layer.

The innermost core of the hair shaft, often absent in fine or light-colored hair. It contributes little to chemical behavior or strength, so its presence or absence is not a reliable indicator of hair health.

A strong chemical bond between sulfur atoms in adjacent protein chains of the cortex. These bonds give hair its shape and strength; permanent waves break them and reform them in a new position during processing.

The ability of hair to absorb and retain moisture, determined largely by the condition of the cuticle. High porosity absorbs quickly but loses moisture fast and takes color unevenly; low porosity resists penetration.

The ability of hair to stretch and return to its original length without breaking. Good elasticity indicates healthy protein structure; poor elasticity warns that hair may not withstand chemical processing.

The pigment produced in the cortex that gives hair its natural color. Eumelanin creates brown and black tones, while pheomelanin creates red and yellow tones; the ratio and amount determine the client's starting level and underlying pigment.

The warm color tones remaining in the hair after natural or artificial pigment is lightened or removed. Identifying it helps the stylist choose a toner or filler so the final result is not brassy or muddy.

The repeating phases of follicle activity: anagen (growth), catagen (transition), and telogen (rest), followed by shedding. Understanding the cycle explains why some shedding is normal and why certain treatments or health conditions cause hair loss.

The natural direction in which hair grows from the scalp, often creating whorls or growth patterns. Cutting against the stream or forcing hair into an unnatural direction can cause uneven lengths or stubborn styling problems.

Dividing the hair into controlled, manageable subsections using clips and a consistent pattern before cutting, coloring, or styling. Clean sectioning improves accuracy, keeps tension even, and prevents missed areas during chemical services.

The angle at which hair is held away from the head while cutting, measured from the scalp. Low elevation builds weight and length, while high elevation creates graduation and layers; consistent elevation is essential for a balanced cut.

The first cut section that establishes the length and shape all other sections follow. It may be stationary, remaining fixed for a solid form, or traveling, moving along the head to create graduation or layers.

A cut in which all hair is trimmed at a single length with zero elevation, producing a strong, solid perimeter line. It creates weight at the ends and requires precise sectioning because any variation shows immediately.

Cutting techniques such as point cutting, notching, or slicing that remove bulk, blend lines, and add movement without changing the overall length. Overuse can thin ends and weaken the shape, so it is applied sparingly.

Shaping hair with heat tools such as blow dryers, curling irons, flat irons, and hot combs. Correct temperature selection, heat protection, and tool cleanliness prevent cuticle damage and burns to the client's scalp.

Setting hair while damp using rollers, pin curls, or finger waves so it dries into a lasting shape. Even tension and thorough drying are critical; dampness left in a set causes frizz and loss of the intended pattern.

A hydrogen peroxide solution that opens the cuticle and develops color by releasing oxygen. Its volume determines lift and deposit strength; using the wrong strength can cause insufficient gray coverage, excessive damage, or scalp irritation.

A small application of a color or chemical product on the skin, usually behind the ear or in the elbow crease, checked after 24 to 48 hours for redness or swelling. It identifies clients who may react allergically before a full service.

A chemical straightener whose active ingredient breaks disulfide bonds in the cortex, allowing hair to be smoothed straight. It requires careful strand testing, thorough rinsing, and a neutralizing shampoo to stop the reaction and restore bonds.

A product applied after a permanent wave or relaxer that stops the chemical reaction and rebuilds disulfide bonds in the new shape. Incomplete neutralization leaves hair weak, limp, or over-processed.

The visible, hardened keratin structure covering the nail bed and protecting the fingertip. Its condition, thickness, and surface affect how products adhere and how safely filing and buffing can be performed.

The pink tissue beneath the nail plate that supplies it with nutrients and blood. Pressure or injury to the nail bed can cause pain, discoloration, or permanent nail deformity, so tools must be used gently.

The area at the base of the nail where new cells are produced and keratinized, forming the nail plate. Damage to the matrix disrupts growth and can leave ridges or permanent irregularities.

The living skin at the base of the nail plate, commonly called the cuticle area. It seals the nail against infection and should be pushed back gently, never cut, unless the client requests and local rules allow it.

A contagious condition of the nail or skin caused by fungi, appearing as thickening, discoloration, or separation of the nail plate. It is a contraindication for nail services, and the client should be referred to a physician.

Any condition or circumstance that makes a service unsafe or inadvisable, such as infection, irritation, or certain medical conditions. Recognizing contraindications protects both the client's health and the practitioner's legal standing.

A structured assessment of the client's skin type, condition, and sensitivities before a facial or makeup service. It guides product selection and identifies areas of irritation or lesions that require medical referral rather than treatment.

A six-point classification of skin type based on response to ultraviolet exposure, from very fair to deeply pigmented. It guides sun-protection advice and helps estimate sensitivity to treatments and light-based services.

The process of destroying most pathogenic microorganisms on nonporous implements using an EPA-registered hospital-grade disinfectant. It requires prior cleaning, correct concentration, and full immersion for the labeled contact time.

The complete destruction of all microbial life, including bacterial spores, usually achieved with an autoclave. It is required for items that contact broken skin or blood and exceeds the standard used for routine implements.

A document supplied with a chemical product that lists its hazards, safe handling, first-aid measures, and disposal instructions. Federal rules require it to be accessible to employees where chemicals are stored and used.

The state body that licenses cosmetologists, nail technicians, and estheticians and enforces Nebraska cosmetology statutes and rules. Candidates should know its licensing, sanitation, and scope-of-practice requirements as outlined in state law.

The legally defined services and procedures a licensed professional may perform within a specific license category. Performing services outside that scope can result in discipline, fines, or license loss under Nebraska law.

Required coursework that licensed practitioners complete to renew their license and stay current on safety, sanitation, and technical practice. Nebraska sets specific hour and content requirements that must be documented at renewal.