Final answer:
Presbycusis is defined as age-related hearing loss, which is the most common form of hearing loss that occurs gradually as a person ages.
Step-by-step explanation:
Presbycusis is indeed defined as age-related hearing loss. It is the most common form of hearing loss that occurs gradually as a person ages. The term 'presbycusis' derives from the Greek words 'presbys' meaning 'old' and 'akousis' meaning 'hearing'.
As people get older, the sensory hair cells in the inner ear gradually degenerate, resulting in a reduced ability to hear high-frequency sounds.