NY Cosmetology key terms

A numbered scale from 0 to 14 that measures how acidic or alkaline a substance is; 7 is neutral, lower numbers are acidic and higher numbers are alkaline. Hair and skin are mildly acidic at roughly 4.5 to 5.5.

A cleansing molecule with one end that attracts water and one end that attracts oil and dirt. Shampoos use surfactants to lift sebum and debris from the hair so water can rinse them away.

A product applied after shampooing that smooths the cuticle, adds moisture or protein, reduces static and makes hair easier to comb. Common ingredients include fatty alcohols, silicones, quaternary agents and hydrolyzed proteins.

The ability of hair to absorb and hold moisture, determined by the condition of the cuticle. Low-porosity hair resists moisture; high-porosity hair absorbs quickly but loses moisture fast and needs gentler chemical service.

The ability of dry hair to stretch and return to its original length without breaking. Wet hair normally stretches further than dry hair; poor elasticity signals damage and means chemicals should be used with caution.

Examination of the client's scalp during consultation for redness, flaking, oiliness, lesions or parasites. Findings decide whether a service can go ahead; contagious conditions or open sores must be referred to a physician.

Dividing the hair into manageable, equal-sized parts held with clips before cutting, coloring or styling. Clean sectioning keeps the work organized and lets each subsection be cut to the same guideline.

The angle at which hair is held away from the head while cutting, also called projection. Holding hair at 0 degrees builds weight, 45 degrees graduates, and 90 degrees or more layers and creates volume.

The first cut section that sets the length for the rest of the haircut, also called the stationary or traveling guide. Every other subsection is cut to match it so the finished shape stays balanced.

A one-length cut in which all hair falls to a single guideline with no elevation, creating a solid, heavy perimeter line. The weight line makes fine hair appear fuller and thicker.

A cut built by stacking subsections at a low elevation so lengths progress from short at the perimeter to longer toward the crown. Graduation adds weight and volume at the ends.

Cutting techniques such as point cutting, slithering and notching that remove bulk, blend lines and soften the ends of a finished shape without changing its overall length.

Shaping and smoothing wet hair with a hand-held dryer plus a brush or comb. Direction, tension and heat control determine volume, smoothness and the final finish of the style.

Shaping hair with a heated curling iron or wand. The iron's temperature must match hair texture and condition, and hair must be clean and dry to avoid scorching and burns.

A thermal service that temporarily straightens curly or tightly coiled hair with a heated pressing comb or flat iron. It is performed on clean, dry, well-conditioned hair in sections from nape to front.

A wet styling technique that creates a temporary S-shaped wave pattern by combing and shaping hair with the fingers and a comb, then clipping it in place until dry.

A wet styling technique in which a small, flat section of hair is rolled into a circle and clipped flat against the scalp. Pin curls create long-lasting waves and curls that can be combed out.

Wet styling with rollers wound under tension so the hair dries into volume, wave or curl. Roller size, base and winding direction control the finished pattern.

A two-step chemical service in which waving lotion breaks disulfide bonds and a neutralizer rebuilds them in a new curl shape. Rod size, processing time and hair condition determine the result.

A strong alkaline product, usually sodium hydroxide or a no-lye alternative, that straightens overly curly hair by breaking disulfide bonds. It requires careful timing, protective cream and thorough rinsing.

A small amount of product applied to the skin, often behind the ear or on the inner arm, 24 to 48 hours before a color or chemical service to check for an allergic reaction.

Cutting a few strands of the client's hair and applying the service product to them before the full service. It predicts processing time and checks how the hair responds to the chemical.

A hydrogen peroxide solution that supplies oxygen to lighten natural pigment and to develop oxidative hair color. Its volume strength controls how much lift and deposit occurs.

The numerical scale, roughly 1 for black to 10 or 12 for the lightest blonde, that describes how light or dark a hair color is. Level describes lightness; tone describes warmth or coolness.

A classification of facial skin as dry, oily, combination or normal based on oil production, pore size and texture. The esthetician selects cleansers, masks and moisturizers to match the client's type.

Removing dead cells from the skin's surface with a scrub, enzyme or gentle acid. It smooths texture and brightens the face; over-exfoliating or scrubbing acne can irritate skin and spread bacteria.

The first step of a facial, using a cleanser matched to the skin type to remove makeup, oil and debris. Basic facials continue with toning, massage, a mask and moisturizer.

The visible, hard keratin structure that covers the nail bed and protects the fingertip. Cosmetologists shape and polish the plate but must not treat diseases of it.

The thin band of dead skin at the base of the nail plate that seals the nail against infection. It should be softened and gently pushed back, never cut, during a standard manicure.

A relaxing manipulation of the hands, wrists and forearms given during a manicure to improve circulation and soften the skin. Movements include effleurage, petrissage, friction, tapotement and vibration.

Reducing the number of germs on a surface or tool to a safe level by washing with soap and water or using a sanitizing product. Sanitation is the required first step before disinfection of implements.

Destroying most harmful microorganisms, though not bacterial spores, on cleaned nonporous implements with an EPA-registered hospital disinfectant. It is required for tools that touch skin or hair.

A product registered with the U.S. Environmental Protection Agency for hospital use that is labeled to kill specific organisms. It must be mixed, used and stored exactly as the label directs.

A standardized document from a product manufacturer listing a chemical's hazards, safe handling, first aid and storage information. It must be kept on file and accessible in the salon.

Treating all blood and body fluids as if they carry infectious disease, using gloves and other barriers for every client. The practice protects both the cosmetologist and the client.

The New York statute that governs licensing and operation of appearance enhancement businesses and sets standards for sanitation, safety and practice. It is administered by the Department of State's Division of Licensing Services.

The list of services a licensed professional is legally permitted to perform. Cosmetologists must stay within that scope and refer diseases of the hair, skin or nails to a physician.

A card or digital file recording the client's contact information, service history, products used and any reactions or test results. It supports consistent service and protects both client and stylist.