The Ultimate Lash Extension Glossary: Terms Every Client Should Know Last updated: July 2026 | Reading time: 8 minutes The lash extension world has its own vocabulary, and it can be confusing if you are a client trying to understand what your lash artist is talking about — or a new artist learning the profession. This glossary covers the most important terms you will encounter. Extension Types Classic extensions: One synthetic extension bonded to one natural lash. The most natural-looking option. Also called 1:1 or one-to-one. Volume extensions: Multiple ultra-fine extensions formed into a fan and bonded to one natural lash. Creates more fullness and density than classic. Fans can be 2D (two extensions) to 6D (six extensions). Mega volume: Fans of 6 to 16 ultra-fine extensions per natural lash. Maximum density and drama. Hybrid extensions: A mix of classic individual extensions and volume fans applied across the lash line. Creates dimension and texture — more than classic, less uniform than full volume. Russian volume: Volume technique using handmade fans, named for its origin in Russia. The artist creates each fan by hand during the appointment. Wispy lashes: A style that mixes different lengths and some "spike" lashes for a textured, effortlessly glamorous look. Very popular on social media. Curl Types B-curl: A subtle, natural curve. Mimics naturally curly lashes. Rarely used as a primary curl in extensions. C-curl: The most popular curl. A noticeable curve that opens the eye without being extreme. Works for most eye shapes. CC-curl: Slightly curlier than C. A good middle ground for clients who want more lift without jumping to D. D-curl: A strong, dramatic curl. Stands up noticeably from the lash line. Excellent for hooded eyes or clients wanting a doll-eye effect. L-curl: Has a flat base with a sharp upward curve. Designed specifically for clients with very straight natural lashes or monolid eye shapes. L+-curl: A variation of L-curl with a slightly more gradual curve. Bridges the gap between L and D. M-curl: A newer curl type with a moderate lift and a slight pinch at the base. Works well on downturned eyes. Materials and Measurements Diameter (thickness): Measured in millimeters. Common sizes: 0.03mm (mega volume), 0.05mm (volume), 0.07mm (light volume/hybrid), 0.10mm, 0.12mm, 0.15mm (classic). Thinner diameters weigh less and allow for more extensions per fan. Length: Measured in millimeters, typically ranging from 8mm to 16mm. Most clients wear 9mm–13mm. Longer lengths are used sparingly for dramatic effect. Faux mink: The most common extension material. Synthetic fibers that mimic the softness of real mink. Lightweight, consistent, and cruelty-free. Silk: A slightly glossier, shinier fiber. Some clients prefer the extra sheen. Flat lashes (cashmere/ellipse): Extensions with an oval cross-section instead of round. They appear darker and fuller while weighing less. Popular for classic sets. Adhesive and Application Cyanoacrylate: The main chemical compound in lash adhesive. Medical-grade versions are used for lash extensions. This is also what some people are allergic to. Cure time: The time adhesive takes to fully harden. Typically 24 hours for full cure, though initial setting happens in 1–2 seconds. Isolation: The process of separating one natural lash from all its neighbors before applying an extension. Proper isolation is the most important safety element in lash extensions. Stickies: When two or more natural lashes are accidentally glued together. This causes pulling, discomfort, and potential damage. A sign of poor technique. Bond: The adhesive connection between the extension and the natural lash. A good bond wraps around the natural lash for 360-degree contact. Retention: How long extensions stay attached before falling out with the natural lash. Good retention means 3–4 weeks of wear. Lash Maps and Styles Lash map: The planned layout of extensions across the lash line — specifying which lengths, curls, and thicknesses go where. Custom maps are designed for each client's eye shape. Cat-eye: A lash map where the longest extensions are at the outer corners, creating an elongated, lifted effect. Doll-eye: The longest extensions are at the center of the eye, creating a wide, open-eyed effect. Natural/open-eye: A balanced map that follows the natural lash growth pattern. No dramatic emphasis on any area. Kim K lashes: A style combining volume with some very long spike lashes for a textured, editorial look. Wet look: Extensions that appear slightly separated and defined, mimicking the look of wet or freshly coated lashes. Maintenance Terms Fill (refill/infill): A maintenance appointment to replace shed extensions and refresh the set. Full set: A complete application of extensions across all suitable natural lashes. Lash bath/lash wash: The process of cleaning extensions with a foam cleanser. Spoolie: A small brush used to groom and separate extensions. Use daily. Lash sealant: A coating applied over extensions to protect the adhesive bond and prolong retention. Explore services: /lash-extensions-toronto/ Shop lash care products: /shop/ FAQ: /faq/ ---

The Ultimate Lash Extension Glossary: Terms Every Client Should Know

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