Don’t know your browlines from your cat eyes? Polycarbonate from titanium? Relax. It’s all here.

glossary of sunglass definitions

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Acrylic plastic lens: a lightweight and inexpensive lens option.

Anti-reflective (AR) coating: a thin coating applied to lenses in order to reduce the amount of reflected light and glare that reaches your eye, as well as the amount of glare visible to others looking at your lenses.

Aviator: a style of sunglasses made popular by pilots that typically have a metal frame, top bar, and large, tinted lenses. Think Maverick in Top Gun. Click here to shop our selection of aviators!


Base tint: a dye embedded in sunglass lenses that creates the color you see when you look at the backside of your shades.

Bridge: the area that arches up between the lenses over the nose and supports the majority of the weight of the glasses. Check out the bridge at work in our sunglass diagram!

Browline: retro sunglasses with a heavy browline and thin lower rims. Celebrities like Bruno Mars and Robert Pattinson are often seen sporting this style. Click here to see our selection of browline sunglasses.


Carbon fiber: a distinct material used for sunglass frames that is very strong and hard to adjust. Carbon fiber sunglasses are ideal for both the adventurous and the accident-prone.

Case: a hard protective box that fits to standard sunglasses size and is intended to keep your glasses from being scratched, bent, broken, or sat on. Click here to see all of our cases!

Cat eye: a retro feminine sunglass style that is distinguished by its upswept outer edges. Popular with 1950s style icons such as Audrey Hepburn and Marilyn Monroe, modern day celebs, and anyone who wants to feel like a celebrity. Click here to browse our selection of cat eye sunglasses!

Clip on: sunglass lenses that clip (or attach) onto your prescription eyeglasses and provide protection from the sun. Click here to see our selection of clip on sunglasses!

Coating: a treatment applied to the surface of your lens to provide additional protection, utility, or style.

  • Anti-reflective coating reduces the amount of distracting reflections bouncing off of your lenses. This type of coating is often applied to  curved lenses.

  • Hydrophobic coating acts as a waterproofing shield by shedding water and sweat that your sunglasses may encounter. This also reduces spotting that may otherwise occur on the lens surface.

  • Mirrored coating gives lenses the appearance of a mirror and can help reduce glare and bright light.

  • Scratch-resistant coating helps prevent polycarbonate and other plastic lenses from scratching.

  • Photochromic coating automatically darkens and lightens the tint of your lenses when the light changes.


Diopter: the unit of a lens’s refractive power, equal to the reciprocal of the lens’s focus length in meters. Used as a measurement to prescribe corrective lenses.

Driving sunglasses: a style of sunglasses designed to decrease eye strain on drivers thanks to lenses that reduce glare and enhance the driving experience. Click here to cruise our selection of driving sunglasses!


Earpiece: the plastic covering encasing the portion of the frames that rests on top of the ear and provides additional comfort. Most commonly seen on metal frames. Click here to see where the earpiece fits on our sunglass diagram!

Endpiece: the part of the frame that connects the lenses to the temples. Check out our sunglass diagram to see the endpiece hard at work!


Fit overs: these sunglasses are for people who already wear corrective lenses. They’re larger than your regular glasses so they can be worn right over them. Find your own pair of fit overs here!


Glare: a condition caused by bright light from a direct or indirect light source (like the sun’s reflection off the water) that causes difficulty in seeing.

Glass: a common material used for lenses that offers excellent clarity and resistance to scratching.


Hinge:  the folding part of the frame that connects the rim to the temples and allows the temples to lay flat along the inside of the frame. Click here to see where the hinge fits in our sunglass diagram!

  • Barrel  hinges are made of interlocking pieces that can be found on the inside face of the frame and are kept together with a small screw. This is the type of hinge most commonly used found on sunglasses.

  • Interlocking hinges are very similar to the barrel hinges, except that the hinge is actually part of the frame itself. Usually found on plastic frames, the joint is molded into the frame, and there are no separate hinge pieces holding the frame together.

  • Spring hinges  use a spring tension to press the temples of the frame closer to the sides of your head.

  • Break-away hinges are made from interlocking plastic parts that separate or “break away” when a significant impact from the outside occurs. These hinges, found mostly on sport sunglasses, will prevent damage.


Interchangeable lens: lenses that can be swapped out of a pair of sunglasses to provide different looks or lens benefits.


Lens: the transparent glass or plastic part of sunglasses that you looks through. Lenses protect your eyes by blocking UV light. Click here to see how the lenses work with the rest of the frame in our sunglass diagram!

Lens size: the width of a lens in millimeters, measured at its widest point.


Melanin polarized lenses: lenses with a highly protective treatment that works against UV radiation, blue light, and glare.

Metal frames: frames made from base metals, copper, or nickel alloys, that are later plated with fine metals, such as gold, to give them a rich finish.


Nose pads: soft plastic pieces that are attached directly to the frame or to the pad arms. They help to keep the frame in its proper position on your face, while also ensuring that the shades fit comfortably. Click here to see the nose pads on our sunglass diagram!

Novelty: wacky, out-of-the-ordinary sunglasses for fun occasions such as parties, Halloween, and New Year’s. Click here to shop our selection of novelty sunglasses!


Optical clarity (acuity): the ability of a lens to deliver a sharp image to the eye.

Oversized: overly large sunglasses with very large lenses and frames. Often spotted on A-list celebs, they come in a variety of styles and prints. Plus they work well for extra sun coverage. Click here to find an oversized style that suits you!


Pad arms: these hold the nose pads in place, but still allow adjustments to help the pads better conform to your nose. Click here to see the pad arms at work in our sunglass diagram!

Peripheral vision: the edges of your visual field.

Polarized lenses: lenses with a special coating that increase visibility by filtering out horizontally-reflected glare. While useful for everyone, polarized lenses are especially beneficial for senior citizens, diabetics, those with sensitive eyes, or anyone who spends hours in the sun or snow. Teens and children under 18 should also jump on the polarized lens trend to protect their eyes. You can learn more with our Polarization Guide and find your own pair by shopping our selection of polarized sunglasses!

Polycarbonate: an extremely strong plastic used for sunglass frames that weighs little and is impact-resistant, making it an ideal selection for those who need a tough and rugged style.


Reading sunglasses: a style of glasses that combine the power of reading glasses with the protection of sunglasses, making them the perfect style for outdoor reading. Click here to shop our selection of reading sunglasses!

Retro Square: an iconic sunglass style characterized by its slightly trapezoidal shape. Suited for both men and women, retro square frames became popular in the 1960s and remain one of the most sought-after styles today. Click here to shop our selection of retro square styles.

Rim: the part of the eyeglass frame that holds the lenses in place and crosses the top of the nose. Click here to see the rim in our sunglass diagram!

  • Full rims are the style most typically found on sunglasses where the lens is completely encased in the rim of the frame.

  • Semi-rim styles are those in which the lens is encased only at the top of the frame.

  • Rimless styles lack a rim entirely. Instead, the lenses are joined together by the bridge and the temples are also attached to the lenses.

Round: a sunglass style characterized by its round lenses. Made iconic by artists such as John Lennon and Lady Gaga, round sunglasses have proven to be a timeless style. Click here to shop our selection of round sunglasses!


Screws: tiny metal fasteners used to connect the temples to the rims and to hold the nose pads in place on eyeglass frames. See where the screws fit into your frames by checking out our sunglass diagram!

Shield: distinctive sunglasses that are defined by their signature one-piece lens. Their frames can be thin, thick, or anywhere in between. Check out our selection here and snag your own pair!

Silicone: a type of flexible and comfortable plastic that is commonly used in nose pads.

Sport: sunglasses that are designed to withstand your active lifestyle. Based on their frame and lens tint, they may even help improve your game. Learn more about what makes a pair of sport sunglasses right for your lifestyle by visiting our Athlete’s Guide to Sunglasses, then click here to find that perfect pair!

Stainless steel: a type of steel commonly utilized in wear. Stainless steel frames can be very thin while still maintaining their strength and flexibility.


Temples: “arm” pieces of the frame that extend over, and sometimes behind, the ears to help hold the sunglasses in place. See how the temples fit into your frames by checking out our sunglass diagram!

Temple tips: plastic coatings that often cover the ends of the temples near the ears to provide comfort. Commonly used with metal frames.

Tints: colors you can apply to your lenses to enhance clarity in different lighting conditions, increase visibility, and reduce glare. For example, brown-tinted lenses enhance depth perception when there is little light. Tinted lenses are not only fashionable, but functional. For more on sunglass tints and their benefits, click here!

Titanium: a type of metal alloy that is very strong and used to make sunglasses that are lightweight and durable.

Top bar: also known as a “sweat bar” or “brow bar,” this is the reinforcing bar that crosses between the two lenses at the top of the frame, on some metal styles. Popular in aviator styles (like these), you can see where the top bar fits into see our sunglass diagram here!


Ultraviolet (UV) rays: energy emitted by the sun that you can’t see or feel.  Extended exposure to UV rays can increase your risk for skin cancer and cause damage to your eyes, making UV protection an important feature to look for in a pair of sunglasses.

UV filter: a lens coating that fights UV radiation and protects the eyes by filtering out the sun’s harmful rays.


Visible light: the part of the sun’s energy that one can see. It is made up of a spectrum of colors: red, orange, yellow, green, blue, and violet.


Wrap around: a type of sunglass frame that curves around the head, from the front to the side. Wrap arounds provide better sun protection than any other type of sunglasses. Click here to shop our selection of wrap arounds!