Absolute pitch (AP), widely referred to as perfect pitch, is an auditory phenomenon characterized by the ability of a person to identify or re-create a given musical note without the benefit of a reference tone.
AP can be demonstrated via linguistic labeling ("naming" a note), auditory imagery, or sensorimotor responses. For example, an AP possessor can accurately reproduce a heard tone on their musical instrument without "hunting" for the correct pitch.
Generally, absolute pitch implies some or all of the following abilities, achieved without a reference tone:
Identify by name individual pitches (e.g. A, B, C♯) played on various instruments.
Name the key of a given piece of tonal music.
Reproduce a piece of tonal music in the correct key days after hearing it.
Identify and name all the tones of a given chord or other tonal mass.
Accurately sing a named pitch.
Name the pitches of common everyday sounds such as car horns and alarms.
People may have absolute pitch along with the ability of relative pitch, and relative and absolute pitch work together in actual musical listening and practice, but strategies in using each skill vary. Those with absolute pitch may train their relative pitch, but there are no reported cases of an adult obtaining absolute pitch ability through musical training; adults who possess relative pitch, but who do not already have absolute pitch, can learn "pseudo-absolute pitch", and become able to identify notes in a way that superficially resembles absolute pitch. Moreover, training pseudo-absolute pitch requires considerable motivation, time, and effort, and learning is not retained without constant practice and reinforcement.