Cosmetology (Kenya TVET CDACC Beauty & Cosmetology) key terms

A scale from 0 to 14 that measures how acidic or alkaline a water-based solution is, with 7 neutral, below 7 acidic, and above 7 alkaline; it governs how hair and skin react to products.

A shampoo formulated near the natural pH of hair and scalp, roughly 4.5 to 5.5, so it cleans without excessive swelling of the cuticle or stripping color.

The outermost layer of the hair shaft, made of overlapping scale-like cells that protect the inner structure and control how much moisture or chemical enters the strand.

The middle and thickest layer of the hair shaft, containing the bulk of the fiber's strength, elasticity, natural pigment, and ability to hold curl or color.

The innermost core of the hair shaft, a soft, sometimes hollow channel that may be absent in fine or light-colored hair and contributes little to strength or appearance.

A strong chemical link between sulfur atoms in neighboring protein chains of the cortex; these bonds give hair its shape and are broken and rebuilt during perming and relaxing.

A weak, temporary attraction between molecules that is easily broken by water and heat, allowing wet sets and blow-dry styling to change shape until the hair dries again.

The ability of hair to absorb and retain moisture, determined by the condition of the cuticle; highly porous hair takes up chemicals fast and loses moisture quickly.

A quick check in which a wet strand is stretched and released to judge how far it extends and whether it returns, revealing the hair's strength and readiness for chemical service.

A common inherited form of hair thinning driven by hormones and genetics, affecting the crown and hairline in men and general thinning in women; it is not treated by salon services alone.

Dividing the hair into clean, controlled subsections with clips before cutting, coloring, or styling so each area is worked evenly and the design stays balanced.

The first cut strand or boundary that sets the length and shape reference for the rest of the section or haircut, also called the guide or perimeter line.

The angle at which hair is held away from the head while cutting; low elevation builds weight and length, while high elevation removes weight and creates layers.

A cutting technique where lengths stack or build up in a wedge shape, usually created by cutting at a consistent low-to-medium elevation along the perimeter.

A texturizing cut made by snipping into the ends of a strand with the tips of the shears, softening a hard line and blending weight without shortening the overall length much.

Cutting with a straight razor to slice strands at an angle, producing soft, tapered ends and movement; it demands control because it can fray or thin porous hair.

A styling method in which damp hair is wound on rollers or formed into pin curls and dried, so temporary hydrogen bonds set the shape until moisture or heat releases it.

Shaping hair with heat tools such as blow dryers, curling irons, and flat irons, using temperature and tension to rearrange temporary bonds into a lasting style.

A small application of a chemical product, usually color or lightener, on the skin 24 to 48 hours before the service to check for an allergic reaction.

A trial application of a chemical service on a small hidden section of hair to preview timing, result, and condition before treating the whole head.

A hydrogen peroxide solution mixed with permanent color or lightener to open the cuticle, develop pigment, and lift or deposit color; its volume strength controls the rate.

A cold perm using thioglycolate and an alkaline pH to swell the cuticle, break disulfide bonds, and re-form them around rollers into a new curl pattern.

A six-point classification of skin tone based on how it responds to ultraviolet light, used to judge sun sensitivity and select safe treatment and waxing parameters.

Any condition, medication, or skin state that makes a service unsafe or inadvisable, such as broken skin, certain prescriptions, or an active infection; service must be postponed or declined.

Separation of the nail plate from the nail bed, leaving a whitish pocket; it is a disorder, not a cosmetic flaw, and a manicure should not be performed over it without clearance.

The hard, visible keratin structure covering the nail bed, made of compacted cells and shaped by the matrix; its surface is what manicures file, buff, and coat.

Reducing the number of microorganisms on a surface or tool to a safe level by cleaning and using an EPA-registered disinfectant; it is the minimum standard for reusable implements.

Destroying most pathogenic microorganisms on nonporous implements with a hospital-grade, EPA-registered product used at the label's contact time; it does not kill all bacterial spores.

The complete destruction of all microbial life, including spores, usually by autoclave or dry heat; it is required for tools that may contact blood or break the skin.

A virus or bacterium carried in blood or body fluids, such as hepatitis B or HIV, that can be transmitted through needlesticks, cuts, or contact with mucous membranes.

A written workplace program required by OSHA that identifies jobs with blood exposure risk and sets out procedures, protective equipment, and post-exposure steps for employees.

A document, now commonly called a Safety Data Sheet under the global harmonized system, listing a product's hazards, safe handling, and first-aid steps; it must be accessible to staff.

The legally defined set of services and procedures a licensed professional may perform; working outside it, such as diagnosing disease, is unlawful and unsafe.

A client's agreement to a service after being told what it involves, the expected result, the risks, and the alternatives, documented before the work begins.

A structured conversation before a service that gathers the client's goals, history, and lifestyle, checks for contraindications, and confirms the plan and price.

Calculating the cost, markup, and profit of products sold to clients, including the difference between wholesale cost and retail price and how it affects salon revenue.

A dated written or digital note of each client visit listing products used, formulas, timing, and results, which supports consistency, follow-up, and liability protection.