Hearing impairment, hearing loss, or Deafness, is a partial or total inability to hear. It is one of the most common medical conditions presenting to physicians. It is caused by many different factors, including, but not limited to, aging, exposure to noise, illness, or chemicals and physical trauma or any combination of these. Audiometry (hearing testing) may be used to determine the severity of the hearing impairment. While the results are expressed in decibels, a physical descriptor, hearing loss is usually described as mild, mild-moderate, moderate, moderately severe, severe, or profound. Conceptually, hearing loss is usually acquired by a person who at some point in life had no hearing impairment. There are a number of measures that can be taken to prevent hearing loss, especially avoidance from exposure to noise, chemical agents, and physical trauma. But, in some cases such as due to disease, illness, or genetics, it is impossible to reverse or prevent. Technological advancements are being made continuously to improve the hearing of those who are hearing impaired. Hearing aids have become more advanced and smaller. There have been developments in the pharmacological management of hearing in response to insult from exposure to noise, chemical agents, or physical trauma. Deafness, which can be functionally described, as the absence of usable hearing acquired either from birth or prelingually, is viewed by many of the deaf community as a condition, not an illness. Some of the newer technologies, such as cochlear implants that provide some hearing for the deaf, have caused controversy in the deaf community. An OSH glossary used in safety and health at work which is, adopted by ILO {102}. The term definition has been obtained from the secondary source