Glossary

Acclimatization: Acclimatization is the period your brain takes to adjust to hearing aids, especially if you've been living with untreated hearing loss for a while. Sounds you haven't heard clearly in years (your own voice, footsteps, refrigerator hum) can feel strange at first. Most people adapt within a few weeks. The process is gradual and very normal.
AI Hearing Aids: AI hearing aids use machine learning to recognize what's happening in your environment and adjust automatically. Walking into a noisy restaurant? The hearing aids know. Stepping outside on a windy day? They adapt. The best AI models also use deep neural networks trained on millions of real-world sound samples to separate speech from noise more effectively than traditional processing.
Audiogram: An audiogram is a chart that shows the results of a hearing test. It maps the softest sounds you can hear at different pitches in each ear and can be used to program hearing aids. Already have one from a previous test? Great. Don't have one? An online hearing test works too.
Audiologist: An audiologist is a healthcare professional with a doctoral degree (AuD or PhD) who diagnoses and treats hearing and balance disorders. They can run full diagnostic evaluations, fit hearing aids, and manage related conditions like tinnitus. Audiologists are one of two licensed professionals who can fit hearing aids in the United States.
Auracast: Auracast is a next-generation Bluetooth standard that lets compatible hearing aids tune into public audio broadcasts at airports, theaters, gyms, churches, and conference rooms. Think of it as picking up a radio station for whatever room you're in. Most premium hearing aids released recently either support Auracast out of the box or will receive it through a firmware update.
Authorized Retailer: An authorized retailer is a seller approved directly by the hearing aid manufacturer to sell genuine devices with full manufacturer warranties. Unauthorized sellers might offer lower prices, but the devices often come with voided warranties, gray-market sourcing, or no professional support. Injoy is an authorized retailer for every brand we carry.
Behind-the-Ear (BTE): Behind-the-Ear hearing aids sit behind the ear and send sound through a tube into the ear canal. They're durable, easy to handle, and powerful enough to fit any degree of hearing loss, including severe and profound. BTEs are often the right call for kids, for anyone who needs serious amplification, or for people who simply find them more comfortable than smaller styles.
BiCROS Hearing Aid: A BiCROS hearing aid is similar to a CROS but designed for people with single-sided deafness and additional hearing loss in their better ear. The microphone on the deaf side sends sound to a hearing aid on the better side, which amplifies both the transmitted signal and the surrounding sound. It addresses two problems at once.
Bluetooth: Bluetooth is the wireless technology that lets hearing aids connect directly to phones, TVs, tablets, and other devices. That means hands-free calls, music streaming, and audio that goes straight into your hearing aids instead of fighting with the room around you. It also enables remote adjustments through a smartphone app, which is part of how remote care works in the first place.
Bundled vs. Unbundled Pricing: Bundled pricing means the price you pay includes the hearing aids plus all programming, adjustments, and follow-up care for a set period. Unbundled means you pay separately for the device and for each visit or service. Bundled is simpler and easier to predict. Unbundled can look cheaper upfront, then add up fast.
Channels: Channels refer to how a hearing aid divides up the sound spectrum to process it. More channels mean finer control over how each frequency band gets amplified, shaped, and cleaned up. Entry-level hearing aids might have 12 channels; premium models can have 24 or more. More isn't automatically better, but for complex hearing loss, it usually helps.
Charging Case: A charging case is the dock that holds and charges rechargeable hearing aids when you're not wearing them. Many cases double as portable battery banks, giving you several extra charges when you're away from an outlet. It's where your hearing aids live overnight.
Completely-in-Canal (CIC): Completely-in-Canal hearing aids are custom-fit devices that sit fully inside the ear canal, with only a small removal handle peeking out. They suit mild to moderate hearing loss and offer a discreet look without going fully invisible. Slightly more room for features than an IIC, slightly more visible. A common middle-ground for people who want a low-profile fit.
Conductive Hearing Loss: Conductive hearing loss happens when sound can't travel through the outer or middle ear the way it should. Common causes include earwax buildup, fluid behind the eardrum, infection, or a problem with the small bones that transmit sound. Many cases are temporary and treatable with medical care, so a checkup with a doctor is usually the right first step.
CROS Hearing Aid: A CROS (Contralateral Routing of Signal) hearing aid is designed for single-sided deafness, where one ear has normal hearing and the other has little to no usable hearing. A microphone worn on the deaf side picks up sound and transmits it to a receiver on the hearing side. It restores awareness of sound coming from the deaf side.
Custom-Molded: Custom-molded hearing aids are made from a unique impression of your ear, so the shell fits the contours of your ear canal exactly. Custom devices include IIC, CIC, ITC, and ITE styles, as well as custom earmolds used with BTE hearing aids. The fit is more secure, more comfortable for many wearers, and harder to dislodge.
Decibel (dB): A decibel is the unit used to measure how loud a sound is. A whisper sits around 30 dB, a normal conversation hums at about 60 dB, and a rock concert can scream past 110 dB. Hearing tests use decibels to measure the quietest sounds you can hear at each pitch.
Directional Microphones: Directional microphones focus on sound coming from in front of you while reducing sound from the sides and behind. The practical result is better speech understanding in restaurants, crowded rooms, and family dinners where everyone is talking at once. Most modern hearing aids adjust their directionality automatically based on what's happening around you.
Domes: Domes are the soft, flexible tips that snap onto the receiver of a hearing aid and sit gently in the ear canal. They come in different sizes and styles, open or closed, vented or sealed, to balance comfort, retention, and sound quality. Picking the right one is a small detail that makes a big difference.
Earmold: An earmold is a custom-fit earpiece made from an impression of your ear canal. It's typically used with behind-the-ear hearing aids and is often the right choice for more significant hearing loss, where a snug seal matters for getting enough amplification without feedback. Earmolds also tend to be more comfortable for long wear once they're broken in.
Feedback Cancellation: Feedback cancellation is the technology that stops the whistling sound hearing aids used to be famous for. Modern systems catch escaped sound before it loops back into the microphone and suppress it automatically. The result is hearing aids that stay quiet when they should and amplify when they should.
First Fit: A first fit is the initial programming of your hearing aids to match your hearing profile. It's the moment your hearing aids stop being generic and start being yours. At Injoy, a licensed hearing care provider handles the first fit by phone or video, then continues to fine-tune from there.
Hands-Free Calling: Hands-free calling lets you take phone calls through your hearing aids without picking up your phone. The hearing aids themselves act as both the speaker and the microphone, so the other person hears you clearly even when your phone is in another room. Not every hearing aid supports it, and Android compatibility lags Apple's, so check the model before assuming.
Hearing Instrument Specialist (HIS): A Hearing Instrument Specialist is a state-licensed professional trained to test hearing, fit hearing aids, and provide follow-up care. Licensing and scope of practice vary by state, but every HIS goes through formal training and certification. They're one of two types of licensed professionals who can legally fit hearing aids in the United States.
Hertz (Hz): Hertz is the unit used to measure the frequency, or pitch, of a sound. Low Hz values represent deep sounds like a bass drum or a man's voice; high Hz values represent higher sounds like a whistle, a child's voice, or birdsong. Most hearing loss starts in the higher frequencies, which is why "I can hear, I just can't understand" is such a common experience.
Hidden Hearing Loss: Hidden hearing loss is when a standard hearing test comes back normal, but you still struggle to understand speech in noisy environments. It's caused by damage to the connections between the inner ear and the brain, not the ear itself. Research is still developing, but it helps explain a frustrating experience plenty of people have.
In-the-Canal (ITC): In-the-Canal hearing aids are custom-fit devices that sit in the lower portion of the outer ear and partially inside the canal. They're a step up in size from CIC styles, which means more room for features like Bluetooth and directional microphones. They fit a wider range of hearing loss, from mild to moderately severe.
In-the-Ear (ITE): In-the-Ear hearing aids are custom-fit devices that fill the outer portion of the ear. They're larger than canal styles, which makes them easier to handle, easier to put in, and capable of housing more powerful technology. They work across a wide range of hearing loss and are often a great choice for anyone who finds smaller devices fiddly.
Invisible-in-Canal (IIC): Invisible-in-Canal hearing aids are custom-fit devices that sit deep in the ear canal and are nearly impossible to see when worn. They're designed for mild to moderate hearing loss and appeal to people who want maximum discretion. The tradeoff is fewer features and smaller batteries, since there's only so much technology that fits inside a device that small.
IP Rating: An IP rating is the standardized measure of how well a device resists dust and moisture. The first number rates dust protection, the second rates water resistance. Most modern hearing aids are rated IP68, which means they handle sweat, rain, and brief water exposure without trouble. They are not, however, swim-ready.
Loss and Damage Coverage: Loss and damage coverage protects your hearing aids if they're accidentally lost, damaged, or destroyed. It's separate from a manufacturer warranty, which only covers defects. Coverage terms vary by manufacturer and model, so it's worth confirming what's included before you buy.
Made for iPhone (MFi): Made for iPhone is Apple's certification for hearing aids that connect directly to iPhones without an extra accessory. MFi devices can stream calls, music, and audio straight to your hearing aids and let you adjust settings from your phone. If you live in the Apple ecosystem, MFi compatibility is worth checking before you buy.
Manufacturer Warranty: A manufacturer warranty is the coverage the hearing aid maker provides directly, typically lasting three years on premium devices. It covers defects and certain repairs, but only when the hearing aids are purchased from an authorized retailer. Buying from an unauthorized seller usually voids the warranty entirely.
Microphone: The microphone is the part of the hearing aid that picks up sound from the world around you. Most modern hearing aids have two or more microphones working together to detect where sound is coming from and focus on what matters. The quality and number of microphones is one of the biggest factors in how well a hearing aid handles noisy environments.
Mild, Moderate, Severe, Profound: These are the four categories of hearing loss, based on the quietest sounds you can hear, measured in decibels. Mild loss ranges from 26 to 40 dB, moderate from 41 to 70 dB, severe from 71 to 90 dB, and profound is anything 91 dB and above. Most people who shop for hearing aids fall in the mild to moderate range, where modern devices make a dramatic difference.
Noise-Induced Hearing Loss: Noise-induced hearing loss is permanent damage to the inner ear caused by exposure to loud sounds, either a single intense event or years of moderate exposure. Concerts, power tools, firearms, and loud workplaces are common culprits. Once the damage is done, it doesn't reverse, but hearing aids can restore a remarkable amount of what's been lost.
Noise Reduction: Noise reduction is a feature that lowers steady background sounds, like fan hum, road noise, or HVAC drone, so the sounds you actually want to hear come through more clearly. It works alongside other features like directional microphones to make noisy environments more manageable. Premium hearing aids do this far better than entry-level models, which is one of the biggest reasons to step up in tech tier.
OTC Hearing Aids: Over-the-counter hearing aids are devices adults can buy directly without a prescription or professional fitting. The FDA cleared them in 2022 for mild to moderate hearing loss, opening up a more accessible entry point for people who want to try amplification without committing to prescription-level care. They're a solid starting place. They're not a substitute for prescription devices when hearing loss is more significant.
Presbycusis: Presbycusis is age-related hearing loss, the gradual decline in hearing that comes with getting older. It usually starts in the high frequencies, which is why understanding speech (especially in noise) often becomes harder before volume itself feels like a problem. It's the most common type of hearing loss, and modern hearing aids address it extremely well.
Prescription Hearing Aids: Prescription hearing aids are medical-grade devices programmed to your specific hearing profile by a licensed hearing care provider. They use the most advanced sound processing on the market and can address hearing loss from mild all the way to profound. Programming, fine-tuning, and follow-up care are part of the package, which is what separates them from OTC devices you fit yourself.
Real Ear Measurement (REM): Real Ear Measurement is a verification process where a small probe microphone is placed in the ear canal to confirm a hearing aid is delivering the right sound levels at each frequency. It's traditionally done in person at a clinic. The fitting itself, the part where the hearing aid is programmed to your hearing, happens through manufacturer software either way.
Receiver: The receiver is the small speaker inside a hearing aid that delivers sound to your ear. In RIC and other receiver-in-canal styles, the receiver sits in the ear canal connected by a thin wire to the main device behind the ear. Receivers come in different power levels matched to your hearing loss.
Receiver-in-Canal (RIC): A Receiver-in-Canal, also known as Receiver-in-the-ear (RITE) hearing aid places the speaker inside the ear canal, connected by a thin wire to a small case that sits behind the ear. RIC is the most popular hearing aid style on the market for good reason: it's discreet, comfortable, packed with features, and fits an enormous range of hearing loss. If you're shopping for hearing aids, there's a strong chance this is the style your hearing care provider will recommend.
Rechargeable Battery: A rechargeable battery is a built-in power source that recharges overnight in a dock, no fiddling with tiny disposable batteries required. Most modern hearing aids run a full day on a single charge, and many cases give you several extra charges on the go. For most people, this is the upgrade they didn't know they needed until they had it.
Remote Care: Remote care is professional hearing aid programming, fitting, and follow-up delivered over phone or video instead of in a clinic. A licensed hearing care provider uses the same manufacturer software a clinic uses, just over an internet connection. It's how Injoy delivers the clinic experience without the clinic visit.
Sensorineural Hearing Loss: Sensorineural hearing loss is caused by damage to the inner ear or auditory nerve, usually from aging, noise exposure, or genetics. It's the most common type of hearing loss and it's permanent, which sounds harsh until you remember that's exactly what hearing aids are built to address. Modern devices restore an enormous amount of what sensorineural loss takes away.
Speech Enhancement: Speech enhancement is the umbrella term for the technology that pulls voices forward and pushes background noise back. It's a combination of directional microphones, noise reduction, and increasingly, AI-powered processing that can isolate speech from the chaos around it. This is the single biggest reason modern hearing aids outperform older ones.
Sudden Sensorineural Hearing Loss: Sudden sensorineural hearing loss is a rapid loss of hearing, usually in one ear, that develops over hours or days. It's considered a medical emergency, and the sooner you see a doctor, ideally within 72 hours, the better the odds of recovering some or all of the hearing. If you experience it, skip the hearing aid conversation and call your doctor first.
Tap Control: Tap control lets you control your hearing aids by tapping them with your finger, usually a double-tap to answer a call, pause music, or activate a voice assistant. It's a feature you forget about until you use it, then it's hard to live without. Available on most premium models from major manufacturers.
Telecoil (T-Coil): A telecoil is a small copper coil inside a hearing aid that picks up magnetic signals from hearing loop systems found in many theaters, churches, airports, and public venues. When the loop is active, sound bypasses the room entirely and goes straight to your hearing aids. If you spend time in venues with looped systems, a telecoil is worth asking about.