9. Glossary

Absolute contraindication — A condition that requires a service to be declined entirely; no modification makes the service safe. (4.3.2)

Acid mantle — The skin's naturally acidic surface layer (pH 4.5–5.5) that protects against bacterial growth and environmental damage. (5.3.1)

AHA (Alpha-Hydroxy Acid) — A water-soluble chemical exfoliant that loosens the bonds between dead skin cells on the surface; includes glycolic, lactic, and mandelic acids. (5.3.1)

Anagen phase — The active growth phase of the hair cycle; follicle is fully active; optimal for laser and IPL hair removal. (6.1)

Autoclave — A device that uses pressurized steam to sterilize instruments; the only salon method that destroys bacterial spores. (2.2.1)

Bactericidal — Kills bacteria; one of three required efficacy claims for salon-use disinfectants. (2.2.2)

BHA (Beta-Hydroxy Acid) — An oil-soluble chemical exfoliant that penetrates the hair follicle; salicylic acid is the primary BHA used in esthetics. (5.3.1)

Catagen phase — The transitional phase of hair growth; follicle shrinks and hair growth ceases; short duration. (6.1)

Cleaning — The first level of decontamination; uses soap/detergent and water to remove visible debris; does not kill pathogens. (2.2.1)

Comedone — A clogged hair follicle; open comedone = blackhead; closed comedone = whitehead. (5.1.2)

Contamination — The transfer of pathogens or foreign matter to a clean surface, person, or product. (2.1.2)

Contraindication — Any condition that makes a particular treatment inadvisable or unsafe. (4.3.2)

Cross-contamination — The transfer of microorganisms from one source to another through direct or indirect contact. (2.1.2)

Dermis — The middle layer of the skin; contains collagen, elastin, blood vessels, nerves, sebaceous glands, sudoriferous glands, and hair follicles. (4.1.1)

Desincrustation — Galvanic current treatment using the negative pole to soften sebum and prepare skin for deep cleansing. (5.2.1)

Disinfection — The second level of decontamination; uses EPA-registered chemicals to destroy most pathogens (not spores) on non-porous surfaces. (2.2.1)

Double-dipping — The prohibited practice of re-inserting a used applicator into a shared wax pot or product container; causes cross-contamination. (6.2.2)

Effleurage — A light, gliding massage stroke used to warm tissue, relax the client, and promote lymphatic drainage. (5.1.3)

Electrolysis — A hair removal method using direct electrical current to destroy individual follicles; the only FDA-recognized permanent hair removal method. (6.3.2)

Emollient — A skin care ingredient that softens and smooths by filling in gaps between skin cells; includes plant oils and ceramides. (5.3.1)

Epidermis — The outermost layer of the skin; composed of five sublayers; provides protection and undergoes continuous renewal. (4.1.1)

EPA (Environmental Protection Agency) — Federal agency that registers and regulates disinfectant efficacy claims; salon disinfectants must be EPA-registered. (3.2.3)

Exposure incident — An event in which blood or other potentially infectious material contacts broken skin, mucous membranes, or the eye; requires immediate response per OSHA protocol. (2.4)

FDA (Food and Drug Administration) — Federal agency that regulates cosmetic product safety and ingredient use. (3.2.3)

Fungicidal — Kills fungi; one of three required efficacy claims for salon-use disinfectants. (2.2.2)

Galvanic current — A continuous direct electrical current used in facial treatments for desincrustation or iontophoresis. (5.2.1)

Hard wax (stripless wax) — A wax type applied thickly, allowed to harden, then removed without a strip; adheres primarily to hair; preferred for sensitive areas. (6.2.1)

High frequency — An electrical device that uses alternating current through a glass electrode to produce antimicrobial effects and stimulate circulation. (5.2.1)

Humectant — A skin care ingredient that draws water into the skin from the environment or deeper tissue layers; includes hyaluronic acid and glycerin. (5.3.1)

Iontophoresis — Galvanic current treatment that uses electrical charge to drive water-soluble products deeper into the skin. (5.2.1)

IPL (Intense Pulsed Light) — A broad-spectrum light-based hair removal method; requires licensing beyond standard esthetics in most states. (6.3.2)

Isotretinoin (Accutane) — A prescription oral retinoid for severe acne; causes extreme skin fragility; absolute contraindication for waxing for a minimum of 6 months after discontinuation. (6.2.2)

Melanocyte — A cell in the stratum germinativum that produces melanin, the pigment responsible for skin color. (4.1.2)

Microdermabrasion — A mechanical exfoliation device using pressurized crystals or a diamond-tip wand to remove the stratum corneum. (5.2.1)

Multi-use item — A non-porous tool or item that can be used on multiple clients after being properly cleaned and disinfected between uses. (2.3.2)

OSHA (Occupational Safety and Health Administration) — Federal agency that regulates worker safety; governs SDS sheets, bloodborne pathogen standards, and PPE requirements. (3.2.3)

Patch test — Application of a small amount of product to a test area (inner wrist or behind ear) 24–48 hours before service to assess for sensitivity or allergic reaction. (3.3)

pH — A measure of acidity or alkalinity on a 0–14 scale; healthy skin pH is approximately 4.5–5.5 (slightly acidic). (5.3.1)

Relative contraindication — A condition that requires modification of a service but does not prevent it entirely. (4.3.2)

Retinoid — A vitamin A derivative that increases cell turnover and stimulates collagen production; causes skin fragility at clinical strength. (5.3.1)

Safety Data Sheet (SDS) — A standardized 16-section document providing hazard information, safe handling, and emergency response data for chemical products; must be accessible to all employees at all times. (3.2.1)

Scope of practice — The legal boundary defining what services an esthetician is authorized to perform; estheticians work on healthy skin and do not diagnose or treat medical conditions. (1.2)

Sebaceous gland — A gland located in the dermis, attached to a hair follicle, that produces sebum (skin's natural oil). (4.1.2)

Single-use item — An item intended for use on one client once, then discarded; includes cotton pads, lancets, wooden applicators, and natural bristle brushes. (2.3.2)

Soft wax (strip wax) — A wax applied in a thin layer, removed with a fabric or paper strip; adheres to both hair and skin; cannot be reapplied to the same area. (6.2.1)

Sterilization — The highest level of decontamination; destroys all microbial life including bacterial spores; achieved in esthetics via autoclave. (2.2.1)

Stratum corneum — The outermost layer of the epidermis; composed of dead, flattened cells; the primary target of exfoliation. (4.1.1)

Stratum germinativum (basale) — The deepest layer of the epidermis; contains cells that divide to produce new skin cells and melanocytes that produce pigment. (4.1.1)

Subcutaneous layer (hypodermis) — The deepest layer of the skin; composed primarily of fat cells; provides insulation, cushioning, and energy storage. (4.1.1)

Sudoriferous gland — A sweat gland; eccrine glands regulate temperature; apocrine glands are located in armpits and groin. (4.1.2)

Telogen phase — The resting phase of the hair cycle; the hair is fully detached from the papilla and will shed naturally; not a viable target for laser hair removal. (6.1)

Universal (Standard) Precautions — An OSHA-based approach to infection control that treats all blood and body fluids as potentially infectious, regardless of the client's stated health status. (2.4)

Virucidal — Kills viruses; one of three required efficacy claims for salon-use disinfectants. (2.2.2)

Wood's Lamp — An ultraviolet light used as a skin analysis tool; different skin conditions fluoresce different colors under UV light. (5.2.1)