deafness

Deafness has varying definitions in cultural and medical contexts. In medical contexts, the meaning of deafness is hearing loss that precludes a person from understanding spoken language, an audiological condition. In this context it is written with a lower case d. It later came to be used in a cultural context to refer to those who primarily communicate with a deafness aid or through sign language regardless of hearing ability, often capitalized as Deaf and referred to as "big D Deaf" in speech and sign. The two definitions overlap but are not identical, as hearing loss includes cases that are not severe enough to impact spoken language comprehension, while cultural Deafness includes hearing people who use sign language, such as children of deaf adults.

== Medical context == thumb|The International Symbol for Deafness is used to identify facilities with hearing augmentation services, especially assistive listening devices.|alt=Stylized image of an ear crossed out with a white bar on a blue background In a medical context, deafness is defined as a degree of hearing difficulties such that a person is unable to understand speech, even in the presence of amplification. In profound deafness, even the loudest sounds produced by an audiometer (an instrument used to measure hearing by producing pure tone sounds through a range of frequencies) may not be perceived by the person. In total deafness, no sounds at all, regardless of amplification or method of production, can be heard.