DC Cosmetology key terms

The first step in infection control: removing visible dirt, oil, and debris from tools, hands, and surfaces with soap and water or detergent before any disinfecting step is attempted.

Using an EPA-registered hospital-grade product on pre-cleaned, nonporous implements and surfaces to destroy most harmful microorganisms except bacterial spores, making shared tools safe for the next client.

A validated process that destroys viable microorganisms, including bacterial spores, on appropriate instruments. Required reprocessing depends on the instrument, intended use and applicable rules; a universal salon rule cannot be inferred from blood contact alone.

A product carrying an Environmental Protection Agency registration number, meaning it has been reviewed and shown to kill specific germs when used exactly as the label directs, including the stated contact time.

Treating every client's blood, body fluids, and soiled linens as potentially infectious, regardless of what is known about that person, and using gloves and other barriers accordingly.

The angle at which a section of hair is held away from the head while it is cut; elevation controls how much layering, weight, and length difference the finished shape has.

The first strand or section cut in a haircut, which sets the length and outline that the remaining sections follow; a guide may stay fixed or move through the cut.

A one-length shape in which all hair falls to the same level at the perimeter, cut with zero elevation to create a solid, heavy weight line.

Cutting methods such as point cutting, notching, and slicing that remove bulk or soften blunt ends without noticeably shortening the overall length of the design.

A cutting technique in which clippers travel along the teeth of a comb to shorten and blend hair close to the head, common on tapered sides and napes.

The classification of facial skin as normal, dry, oily, or combination, judged by oil production, pore size, and texture, which guides product selection and treatment planning.

A six-point rating of how skin responds to ultraviolet light, used to estimate sun sensitivity and the risk of pigmentation changes before waxing, peels, or light treatments.

Removing dead cells from the skin surface with scrubs, enzymes, or acids to smooth texture and brighten the complexion; too-frequent or harsh exfoliation irritates and thins skin.

A condition that makes a service unsafe or unwise, such as broken skin, sunburn, or a contagious infection; the professional must recognize it and refuse or adapt the treatment.

A tube-shaped pocket in the skin where a hair grows; its base holds the bulb, papilla, and matrix, where dividing cells build the hair shaft.

Pigment made by melanocytes in the hair bulb that gives hair its natural color; eumelanin produces brown and black, while pheomelanin produces red and yellow.

A sulfur-containing structural linkage in hair proteins that contributes to shape and strength. Permanent-wave and thio systems use reduction and oxidation, while hydroxide relaxing changes bonds through a different chemical process.

The client's documented agreement to a service after being told its risks, benefits, alternatives, and expected result, protecting both the client and the professional.

The services a licensee is legally allowed to perform under a given license; working outside those limits is unlicensed practice and can bring fines or license loss.

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

A number from 1 for black to 10 for lightest blonde that describes how light or dark a hair color looks, separate from its warmth or coolness.

The warm, cool, or neutral character of a color, such as ash, gold, beige, or red, usually shown by a letter or second number after the level in a formula.

The warmth already inside the hair, described as red, orange, or yellow, that appears as natural melanin is lifted and must be factored into any lightening formula.

A manufacturer-directed skin allergy test for a hair dye, performed as its instructions require. FDA advises a 48-hour observation period before dyeing; this does not mean that every lightener or relaxer should be applied to skin for testing.

A trial on one small section of the client's hair to preview how a color or lightener will develop, confirming the formula and timing before the whole head is treated.

Shaping and drying damp hair with a hand-held dryer and brush, using tension and direction to smooth the cuticle, add volume, or turn the ends under or out.

Using heated tools such as curling irons, flat irons, and hot combs to change hair shape temporarily; the tool's heat and the hair's texture must be matched to avoid damage.

Combing hair in short strokes from the ends toward the scalp to build a cushion of volume that supports an updo; the tangles must be removed gently afterward.

A 0-to-14 measure of acidity and alkalinity; hair and scalp do best with mildly acidic products near pH 4.5 to 5.5, which help the cuticle lie smooth.

The cleansing agent in shampoo whose molecules bind to both water and oil, letting oily soil lift off the hair and scalp and rinse away with water.