Between C curls, wispy styles, under-lash application, and lash mapping, it can feel like everyone else got the glossary except you. Let's fix that.

Consider this your go-to reference for all things lash.

A

Adhesive Glue
The glue used to attach lash extensions or segments to the natural lash. In DIY under-lash systems, the adhesive is applied along the natural lash line and allowed to become tacky before segments are placed. FlutterHabit's Made for This® Adhesive is formulated for up to ten days of wear.

Application angle
The direction from which you approach the lash line when placing extensions or segments. In under-lash application, segments are placed from below the natural lash, looking slightly downward into a mirror. Getting the angle right is one of the key skills in DIY application.

B

Bond
Shorthand for lash adhesive. In the context of DIY lash extensions, "the bond" often refers specifically to the adhesive in its tacky state, the stage at which it grips properly and provides secure hold.

Bond time / Tack time
The waiting period after applying adhesive and before placing lash segments. Typically 20-30 seconds. Allowing the bond to reach the tacky stage is one of the most important steps in DIY lash application and the most commonly skipped.

C

C Curl
A lash curl type that produces a gentle, natural-looking upward curve. C curl lashes mimic the shape of a naturally curled lash. A good choice for everyday, natural looks and for eye shapes that are already open.

Clamp
The step at the end of lash application, where you press your natural lashes and segments together using your fingertips and hold for 10-15 seconds. The clamp melds the bond and blends the natural lash with the extension for a seamless result.

Curl type
The degree of upward curve in a lash extension or segment. Common curl types range from J (barely curved, most natural) to C (moderately curved) to D (dramatically curved). Curl type significantly affects how open and lifted the eye appears.

Cluster
A term sometimes used interchangeably with "segment" or "lash segment," a small grouping of lash fibers applied together along the lash line. FlutterHabit refers to their product units as lash segments.

D

D curl
A lash curl type that produces a dramatic, pronounced upward curve. D curl lashes create more visible lift and openness than C curl, making them particularly effective for hooded eyes, monolid eyes, and looks where maximum impact is the goal.

DIY lash extensions
Lash extensions designed for self-application at home, as opposed to professional salon application. DIY systems use pre-made segments or fans that can be applied along the lash line using a bond adhesive. FlutterHabit's under-lash extension system is a leading example of this category.

Doll-eye effect
A lash look characterized by maximum volume and length in the center of the lash line, creating the appearance of large, round, wide-open eyes. The Happy (Medium)® from FlutterHabit is designed with a doll-eye profile.

E

Extension
In the lash context, any fiber or segment added to the natural lash to increase length, volume, or both. Extensions can refer to salon-applied individual fibers or at-home segment systems.

F

Faux mink
A synthetic lash fiber designed to mimic the softness, flexibility, and natural appearance of real mink fur, without using animal fur. Faux mink is the most common material used in quality DIY lash extensions. FlutterHabit lashes are handmade to be soft and lightweight, consistent with faux mink quality standards.

Fan
A pre-made grouping of individual lash fibers arranged in a fan shape, used in volume lash techniques. In volume salon work, fans are created by the technician. In DIY systems, pre-made segments function similarly.

Fill
A salon appointment scheduled to replace shed extensions and fill in gaps as natural lashes complete their growth cycle. Typically needed every two to three weeks. Not applicable to DIY under-lash systems, which are fully removed and reapplied as a set.

Flat lash
A lash extension with an oval or flattened base rather than a round one, designed to bond more surface area to the natural lash. Creates a bolder, slightly more dramatic look with less weight.

G

Growth cycle
The natural cycle of lash growth and shedding. Each natural lash follows a growth phase (anagen), transition phase (catagen), and resting/shedding phase (telogen). According to a 2024 review in the Journal of Cosmetic Dermatology, the anagen phase lasts roughly 4–10 weeks, catagen lasts about two to three weeks, and telogen lasts several months — with the full cycle typically taking 4–11 months to complete. Lash extensions shed along with the natural lash during this cycle.

H

Handmade lashes
Lash extensions or segments crafted by hand rather than by machine, typically resulting in softer fibers, more natural movement, and better quality control. FlutterHabit lashes are handmade.

Hybrid lashes
A salon technique that combines individual lash extensions with volume fans for a textured, wispy result between natural and full-glam. Not applicable to DIY systems, but useful to understand when comparing salon options.

I

Individual extensions
Lash extensions applied one fiber at a time by a salon technician, bonded to each individual natural lash. The most precise and natural-looking salon method, also the most time-intensive and expensive.

Inner corner
The area closest to the nose on the lash line. In lash application, the inner corner typically calls for shorter, lighter segments to avoid an unnatural or heavy look.

L

Lash band
The strip at the base of strip lashes that runs the length of the eye. The band is what gets glued to the lash line in traditional strip lash application, and what's visible up close when strip lashes are worn. Under-lash extension systems like FlutterHabit's have no visible band.

Lash lift
A salon treatment that semi-permanently curls natural lashes upward using a chemical process. Different from lash extensions, no fibers are added. A lash lift can be done before applying DIY lash extensions for added curl in the natural lash.

Lash line
The edge of the eyelid where natural lashes grow. In under-lash application, segments are placed along the underside of the lash line.

Lash mapping
The practice of planning which lash styles and lengths go where along the lash line before application begins. A basic lash map typically places shorter lengths at the inner corner, gradually increasing to the longest lengths at the outer center, then tapering at the outer edge.

Lash segment
A small, pre-made grouping of lash fibers designed to be applied to one section of the lash line. FlutterHabit's products are lash segments, ultra-light, handmade units placed beneath the natural lash line.

M

Mink lashes
Lash extensions made from real mink fur. Less common now due to ethical concerns; most quality lash brands use faux mink (synthetic) instead, which achieves a similar soft, natural appearance.

Monolid
An eye shape with little to no visible crease above the eye. Common in people of East Asian descent. Monolid eyes benefit from lashes with strong curl (C or D curl) that create visible lift and definition against the lid.

N

Natural lash
Your own biological lash, as distinct from any extension, segment, or false lash applied to it. Lash extension health is measured in part by the impact on natural lashes over time.

O

Outer corner
The area of the lash line closest to the outer edge of the eye, near the temple. In most lash styles, the outer corner is where length is emphasized for a lifted or cat-eye effect.

P

Pre-glued lashes
Lash segments or strips that come with adhesive pre-applied, eliminating the separate bonding step. FlutterHabit offers The Sticktionary Edition, a pre-glued under-lash extension for even faster application.

R

Retention
How well lash extensions or segments maintain their bond over time. Good retention means lashes stay in place for their intended wear period. Retention is affected by prep quality, adhesive application, aftercare, and environmental factors like humidity and oil exposure.

Removal
The process of safely detaching lash extensions or segments from the natural lash. For FlutterHabit, removal is done using Lash Off™ Removal Spray or Removal Balm, which breaks down the bond without damaging natural lashes.

S

Segment
See "lash segment." FlutterHabit's terminology for their individual lash units.

Spikes / spiked lash
A lash style with defined, separated points rather than a uniform, blended look. Creates a more editorial, textured appearance. FlutterHabit's The Diva is described as a spiked, tapered style.

T

Tacky / tack time
The state of lash adhesive after it has been applied and allowed to partially dry (sticky enough to grip but no longer wet). Applying lash segments to tacky (not wet) adhesive is essential for proper hold. See also: bond time.

Tapered lash
A lash style in which the fibers are thicker at the base and thinner at the tips, creating a more natural, graduated appearance. The Bestie and The Diva are described as tapered styles in FlutterHabit's range.

U

Under-lash application / under-lash extensions
A method of applying lash segments beneath the natural lash rather than on top of the lash line. Under-lash application produces a more seamless result with no visible band, and is considered gentler on natural lashes because no adhesive touches the waterline or individual natural hairs directly. FlutterHabit pioneered this method for DIY lash extensions.

V

Volume lashes
A salon technique where multiple ultra-fine fibers are grouped into fans and applied to a single natural lash, creating a fuller, denser look than classic individual extensions. Not a DIY method, but relevant for understanding the comparison to at-home systems.

W

Wispy lashes
A lash style characterized by uneven, feathered lengths that create a textured, dimensional look rather than a uniform curtain of lashes. Wispy styles blend natural and longer fibers for an undone, fluttery effect. Willow from FlutterHabit, described as a piecey, soft black lash, falls into this category.

Frequently Asked Questions

What's the difference between lash segments and lash clusters?
The terms are often used interchangeably in the broader lash industry. FlutterHabit uses "lash segments" to describe their individual lash units. Both refer to pre-made groupings of lash fibers applied along the lash line, as opposed to individual fiber application used in salon settings.

What does "under-lash" mean?
Under-lash refers to a method of lash application where segments are placed beneath the natural lash rather than on top of the lash line. This produces a seamless, band-free result that looks more like salon extensions than traditional false lashes.

What is faux mink and is it better than synthetic?
Faux mink is itself a type of synthetic fiber, specifically engineered to mimic the softness and natural movement of real mink fur. It's generally considered a higher quality option than standard synthetic fibers, which can look more obviously artificial.

What curl type is best for natural-looking lashes?
C curl produces the most naturally flattering result for most eye shapes, visible lift without looking overly dramatic. D curl is a better choice when maximum openness and lift are the priority, such as for hooded or monolid eyes.

What is lash mapping and do I need to do it?
Lash mapping is the practice of planning which lengths go where before you start applying. For a first-time application, a simple map — shorter at the inner corner, longest in the center-outer area, tapering at the far outer edge — is enough to guide placement.

What is the difference between a lash lift and lash extensions?
A lash lift chemically curls your existing natural lashes upward without adding any fibers. Lash extensions (salon or DIY) add length and volume with additional fibers. A lash lift can be done in advance of wearing DIY extensions to add curl to your natural lashes as a base.