Hearing Glossary: Terms From Tests, Devices and Accessibility

The ear and hearing

• Outer ear — The visible part of the ear (the pinna) and the ear canal. It collects sound and channels it to the eardrum.¹ Read more
• Ear canal — The short tube from the opening of the ear to the eardrum. Its skin makes earwax, which protects it. Read more
• Earwax (cerumen) — A natural substance made in the ear canal that traps dust and germs and usually clears itself. Objects such as cotton buds can push it deeper. Read more
• Eardrum (tympanic membrane) — A thin membrane at the end of the ear canal. It vibrates when sound reaches it and passes the vibration to the middle ear.¹ Read more
• Middle ear — The small air-filled space behind the eardrum. It holds the three ossicles and connects to the back of the nose through the Eustachian tube.¹ Read more
• Ossicles — Three tiny bones in the middle ear (malleus, incus and stapes) that carry vibration from the eardrum to the inner ear.¹ Read more
• Eustachian tube — A narrow channel between the middle ear and the back of the nose. It opens briefly, for example when swallowing, to balance air pressure on both sides of the eardrum. Read more
• Inner ear — The deepest part of the ear. It contains the cochlea, for hearing, and the balance organs.¹ Read more
• Cochlea — The snail-shaped, fluid-filled organ of hearing in the inner ear. It turns vibration into nerve signals.¹ Read more
• Hair cells — Sensory cells inside the cochlea that respond to vibration and trigger nerve signals. In humans, damaged hair cells do not grow back.⁴ Read more
• Auditory nerve — The nerve that carries signals from the cochlea to the brain, where they are recognised as sound.¹ Read more
• Bone conduction — Sound reaching the inner ear through vibration of the skull bones rather than through the ear canal and middle ear. Read more
• Decibel (dB) — The unit used to describe how loud a sound is. The scale is logarithmic: every 10 dB step is a large change in sound energy.⁴ Read more
• Frequency (Hz) — How many times per second a sound wave vibrates, measured in hertz. It is heard as pitch: higher frequency, higher pitch. Read more

Hearing tests

• Audiogram — A chart of a hearing test result. It shows the softest level a person heard at each frequency, for each ear.⁶ Read more
• Hearing threshold — The softest level at which a person can detect a given sound during a test.⁶ Read more
• Pure-tone audiometry — The standard hearing test: tones at different pitches are played, and the person signals when they hear one. The results form the audiogram.⁶ Read more
• Speech audiometry — A test of how well a person hears and repeats words at different levels, rather than tones.⁶ Read more
• Tympanometry — A test that measures how the eardrum moves when air pressure in the ear canal changes. It gives information about the middle ear.⁷ Read more

Hearing loss and related conditions

• Conductive hearing loss — Hearing loss caused by a problem that stops sound passing through the outer or middle ear. Read more
• Sensorineural hearing loss — Hearing loss caused by changes in the inner ear or the auditory nerve. Read more
• Mixed hearing loss — A combination of conductive and sensorineural hearing loss in the same ear. Read more
• Presbycusis — Age-related hearing loss. It usually develops gradually, in both ears, and affects high pitches first.³ Read more
• Noise-induced hearing loss — Hearing loss caused by very loud sound, either at once or through long exposure over time.⁴ Read more
• Sudden hearing loss — A rapid loss of hearing, usually in one ear, over hours to a few days. It needs prompt medical attention. Read more
• Tinnitus — Hearing a sound such as ringing, buzzing or hissing that has no outside source. It is a symptom, not a disease.⁵ Read more
• Hyperacusis — Reduced tolerance to everyday sounds, so that ordinary noise feels uncomfortably loud or painful. Read more

Hearing devices

• Hearing aid — A small electronic device worn in or behind the ear that makes sounds louder and shapes them to a person's measured hearing.² Read more
• BTE (behind-the-ear) — A hearing aid style where the main body sits behind the ear and sound travels through a tube to the ear canal.² Read more
• RIC / RITE (receiver-in-canal) — A hearing aid style with a small body behind the ear and the receiver (speaker) placed in the ear canal, connected by a thin wire. Read more
• ITE / ITC / CIC (in-the-ear) — Hearing aid styles that sit inside the outer ear or the ear canal, from larger in-the-ear to completely-in-canal models.² Read more
• Receiver — The part of a hearing aid that produces the sound in the ear. It is a small speaker.²
• Dome — A soft, flexible tip at the end of a hearing aid receiver or tube that holds it in place in the ear canal. Read more
• Earmold — A custom-shaped piece made from an impression of the ear, used to hold a hearing aid's sound outlet in the ear canal.² Read more
• Feedback — Whistling that happens when amplified sound leaks out of the ear and is picked up again by the hearing aid's microphone.
• Compression — A hearing aid feature that amplifies soft sounds more than loud ones, so soft speech is audible and loud sounds stay comfortable.
• Cochlear implant — A surgically implanted device that stimulates the auditory nerve electrically. It is used when a hearing aid no longer helps enough.

Connectivity and accessibility

• Telecoil (T-coil) — A small coil in some hearing aids that picks up sound from a hearing loop or a compatible phone, without background noise.⁸ Read more
• Hearing loop — A wire installed around a room that sends sound as a magnetic signal straight to hearing aids with a telecoil.⁸ Read more
• Remote microphone — A microphone worn by a speaker or placed on a table that sends speech directly to hearing aids, making it clearer in noise or at a distance.⁸
• MFi (Made for iPhone) — Apple's system for connecting hearing devices directly to iPhone and iPad for calls, audio and settings.⁹ Read more
• ASHA — Audio Streaming for Hearing Aids, a protocol for streaming audio from Android devices to compatible hearing aids.¹⁰ Read more
• Bluetooth LE Audio — A newer generation of Bluetooth audio designed for lower power use. It includes support for hearing aids and for broadcast audio.¹¹ Read more
• Auracast — The broadcast audio feature of LE Audio. One source can send sound to any number of compatible devices nearby, for example in a hall or at a gate.¹¹ Read more
• Live captions — Real-time text of speech shown on a phone, computer or TV screen, created automatically by speech recognition.⁸ Read more