The ability possessed by some people to describe one or more heard pitches by their note names without error. This is sometimes regarded as a magical ability but is no more remarkable than the ability to name a colour, and like that skill can be learnt by most children and even some adults. It is a rarer skill simply because it is less practised. Some people have a more extreme form where they can not only name the note heard but tell you whether it is flat or sharp. Some even feel discomfort if it incorrect. This "gift" is occasionally described as absolute pitch. It seems to be common among children with autism.
Web Links 
