Cellulose Acetate is a plant-based plastic made from cotton and wood pulp that is hypoallergenic.  Acetate is known for being lightweight yet strong, and for holding frame adjustments very well.  Acetate also has the widest range of color possibilities: from transparent to opaque, simple monocolors to complex patterns, and multi-layer laminations.


The clarity or sharpness of vision provided by various lens materials and/or coatings.


Consists of polymers of acrylic acid or acrylates. Sunglass frames can be made from this.


A light and soft metal with high processability in production.  While 40% lighter than titanium, it is inferior in terms of strength and corrosion resistance.  Used for many years in the manufacturing of temples.

Amber Lens

Recognized as effectively improving acuity in scattered blue lighting conditions caused by haze, smog or fog. Offering an enhanced clarity in high glare conditions; these are a popular choice for activities such as boating, skiing, and driving.

Anti-Reflective Coating (AR)

An optical coating typically applied to the lens surface of eyewear, in an effort to reduce reflection.


Also referred to as the Temple; this piece attaches to the frame and stretches behind the wearer’s ears, holding sunglasses in place. 


A frame shape used by the US air force that has become an eyewear icon.



Backside Coating

Applied to back of polycarbonate lenses to prevent scratching.

Barrel Hinge

A common hinge connecting the temple and the frame of sunglasses.

Base Curve

Defined in sunglass terminology as being the amount of curve found in any sunglass frame. A California Classics style has a low base curve; while sports styles typically have a high base curve and are commonly referred to as wrap-around sunglasses.

Base Tint

Dyes introduced during lens making process to establish lens coloring.


Space between sunglass lenses, extending across/over the wearer’s nose. Designed to support a majority of frame weight.

Brown Lens

Also referred to as an Amber Lens, this lens color is believed to enhance clarity, lessen glare and best for outdoor activities.



Carbon Fiber

A common term used to identify carbon fiber reinforced polymer, known for its strength-to-weight ratio. i.e., highly durable & lightweight.


A manufacturing process mainly used to create end pieces or ornamental parts. A processing method in which beryllium copper or titanium is melted then cooled in a mold to form the parts.

Cat Eye 

A retro frame style in which the outer edges of the almond shaped lenses are upswept. Also called the 'Monroe style' as the style was recognizably worn by Marilyn Monroe in a film.

Clear Lens

Referring to a lens that has no coloring or tinting. Can (and should) provide 100% UV Protection.


A treatment applied to the surface of your lens to add functional protection.

  • Anti-Reflective (AR)- eliminates reflections from front and back of lens to block glare.
  • Hydrophobic- repels water, sweat and reduces spotting on lens surface.
  • Scratch Resistant- protects lenses from abrasions and scratches with a resin film 


A coating applied to outside lens that appears mirrored with various color tints, such as blue, gold, red, green or purple.

Colored Transparent Frame

A type of frame color that is semi-transparent with a color tint. 

Constant Density

Refers to the uniform tinting of lenses, an alternative to gradient tinting.


The varying degrees of tones and values in eyesight. Lens colors will directly affect the wearer’s perception of contrast; which can improve or diminish vision acuity dependent upon lighting conditions.

Core Wire

The wire frame inside of acetate temples. Some styles show off this underpinning in a clear acetate.




Double Bridge

A two-piece bridge design that adds stability and classic design.

Double Gradient

Refers to a lens, which possesses a tint across both top & bottom while having a light tint through the middle.


A very light aluminum alloy, inferior to titanium in strength and corrosion resistance, but lighter in weight. 




Typically a plastic or rubber coating or sleeve that resides along the length of the temple resting on the wearer’s ear. Most commonly seen on sunglasses with a metal or wireframe or temple.


Residing on the outer sides of the frame surrounding the lenses, this portion of the frame is used to attach the temples to the front part of the sunglass frame.


Tiredness or fatigue of the eyes, which can be avoided or drastically minimized with appropriate colored lenses.

Eye Wire

The piece that holds the lens in place. It varies dramatically from one from to another.


Flash Mirror Coating

Another term for a standard mirror lens coating applied to lenses, typically in silver, blue or gold.


The portion of sunglasses that lenses rest within, which temples are attached to via end pieces and/or hinges.

Frame Arm

Extends behind the ear, holding sunglasses in place while being worn.

Frame Rims

Part of the sunglass frame in which lenses are inserted.

Full Rim

Referring to a sunglass style that possesses an entirely enclosed lens.      




Can be caused by a direct or reflected light source, causing difficulty seeing. 

Gradient Tint

Provides a transitioning lens tint quality, typically darker above, and lighter below.

Gray Lens

A neutral tone believed to provide the truest colors and is an all-purpose tint. Believed to provide the highest level of glare resistance, while not enhancing contrast.

Green Lens

Known to provide increased contrast in low light situations, while minimizing eyestrain in bright light. Minimal blue light is filtered by green lenses.


Half-Rimless Sunglasses

Referring to eyewear that possesses only the upper portion of a frame rim. Typically found with wireframe eyewear. 

Hard Cases

Refers to a style of sunglasses case which has a hard outer shell, frequently 'snap' close upon placing pressure on the lid.

Hard Coating

Applied to lenses to increase resistance from scratching and/or breakage.

The open & close part of the frame that connects the rim to the temples.

  • Flex Hinges- uses an internal spring to give you extra durability with greater flexibility. 
  • Light Ray Hinges- are made of ultra-flexible and resilient titanium. 
  • Mono-Block Hinges- are made from a single block of metal so there’s less chance of breakage.
  • Pinless Front Hinges- made of nickel-silver are used in acetate or nylon frames. 
  • Rivet Hinges are fixed to the front or temples using rivets inserted into the hinges’ twin holes to create a vintage look. 

Hydrophobic Lens

Achieved by applying a special coating to the lens that will repel moisture and prevent spotting of the lens.




Standard for determining the ability of any material to withstand impact without chipping, shattering, fracturing or breaking.

Interlocking Hinges

Built into the temple of the sunglasses, operates similarly to a barrel hinge. Will appear like a small pin screwed into the frame.


Common component when making mirror coatings.




Part of eyewear that you see through. 

Lens Materials

  • Glass- used to be the material of choice but has been replaced by lightweight, durable high-tech plastics that offer optimum clarity.
  • Polycarbonate- is a type of high-index plastic thatís thinner, lighter and impact resistant.
  • HD- is a digital lens that provides the highest level of detail and clarity, especially in high index prescriptions. 

Lens Tint

Refers to the density and shading of lenses.



Memory Metal

A metal alloy used for frames thatís usually made from titanium and nickel. It keeps its shape while offering a fit thatís lightweight, strong and comfortable.

Metal Frame

Refers to a frame made of metal or wire,  common among many aviator styles of sunglasses. Metal frames include sleek silver, nickel, bronze, titanium, or steel. They can be painted or finished with a coating for a matte or brushed effect.


A material commonly used as a cleaning cloth for lenses as well as storage bags with draw-string closures for sunglasses.

Mirror Coating 

A lens coating which makes the lens reflective like a mirror.  By reducing the amount of sunlight that passes through the lens, glare is limited; as such, this coating is often used for sports sunglasses.



Nickel Silver

An alloy of nickel and zinc. It is more rigid than other mixed metals and is often used in eyewear for hinges, earpieces, and bridges.

Nose Pad

Present on many styles of sunglasses refers to an oval plastic piece attached to Pad Arm designed to enhance comfort and support weight of the frame.

Nylon Fiber

A lightweight and resilient alternative to acetate frames that comes in a wide array of colors and styles.

Nose-Pad Arm
The arm piece connecting the front piece and the nose pad.  It can be adjusted to position the frame.



Pad Arms

A piece of material extending from the frame rim used to attach the nose pad, capable of providing a customized fit for the wearer.


The ability to undergo a reversible change in color (or shade) when exposed to specific frequencies or intensity of light, allowing the effect to only occur in sunlight rather than artificial light. Often applied to lenses, however, after long-term exposure to intense sunlight, the darkening effect will become irreversible.


The ability to restrict and reflect specific frequencies of light rays.            

Polarized Lens

Sunglasses treated with a coating that filters out horizontally reflected glare to give you sharper details, enhanced colors, and enhanced depth perception.

Polycarbonate (PC):

A notoriously resilient plastic created by various carbonate groups. Classified as a synthetic resin. Commonly used to manufacture lenses due to its scratch resistant, lightweight qualities.

Precision Laser Welding 

A welding technique which utilizes laser energy. Far more precise than conventional welding, it joins parts without damaging the material.  It provides a much stronger weld, and allows for the most delicate of pieces to be connected. 

Protection Index

Refers to the level of UV eye protection in sunglasses. Always choose lenses that are rated UV400 or higher which means theyíll block 99.9% of UV rays.



Reflected Glare

Caused by reflected light sources, generally generating a much stronger, and more damaging glare than the originating source. (i.e., sunlight reflected off of water will cause more damage to the eyes than the original light waves.)
RETRO is a vintage look characterized by rounded shapes, rivets, and etched metal or coin edge tooling.

Revo Lens

Refers to a mirrored coating that reflects a coloring. I.e., red revo, blue revo, gold revo.


The part of the frame responsible for holding the lens. It also determines the shape of the lens.


Referring to sunglasses that have only a partial frame rim into which lenses are inserted.

Rose Lens

Similar to brown and amber lenses, in that it effectively scatters blue light and enhances contrast.




This is a term used to identify the ability of a material to withstand scuffs and abrasions. Can be a  Coating applied to lenses, or a quality possessed by materials used as lenses. 


Synonymous with half-rim and rimless; referring to a frame style that forms only the upper portion of the frame rim, common with wireframe styles.

Side Pieces

Another term for the Temple of sunglasses, which extend over and behind the wearer’s ears.

Smoke Tint

Common reference to the shading applied to the lens to darken/absorb light rays.

Soft Cases

Refers to sunglass cases made of flexible materials. Available in numerous types of materials, patterns and sizes.

Spring Hinge

A high-quality hinge alternative that provides added comfort and durability. Functions in a manner allowing the joint more flexibility. 

Sweat Bar

Common frame piece in metal sunglasses used to connect the lenses. 

Sunglass Straps

An accessory for sunglasses that attaches to the temple-tips,  used to allow sunglasses to rest around the wearer's neck. Can be found in useful floating materials, which will prevent losing sunglasses in bodies of water.




Piece of sunglasses extending behind the ears, enabling them to stay in place.

Temple Tips

Made of soft rubber or plastic and applied to the tip of the temple for added comfort, also assists in keeping sunglasses in place while worn. 

Top Bar

Portion of frame that joins lenses.

Transparent Frames

A sunglass frame that is clear plastic, often used in combination with a color cast. Also called Translucent Frames.



Ultraviolet Rays (UV)

Harmful rays of the sun, consisting of UVA, UVB & UVC. Whereas UVC is absorbed by the earth’s ozone layer, both UVA & UVB are harmful to the eyes and after prolonged exposure are believed to lead to numerous health conditions.

UV Protection

Can be applied as a lens coating, or embedded into the lens; successfully blocking all UV rays.


Visor Clips

A sunglass accessory used to attach sunglasses to vehicle visors for easy storage and reach.



Yellow Lens

Dramatically enhances depth perception and perception in low light conditions. Frequently used for driving glasses.