the.com/perfect pitch

means The rare ability to identify or sing a musical note correctly without any reference tone to compare it to.

from 'Pitch' for a tone's highness or lowness dates to the 1500s, borrowed from the literal sense of throwing or fixing something in place — a note 'pitched' at a certain level. 'Perfect' here keeps its old sense of 'complete, flawless,' as in perfect fifths and perfect circles. The phrase 'perfect pitch' itself is a 19th-century musical-theory coinage, distinguishing the rare absolute kind from the common 'relative pitch' everyone can train — no myth to debunk here, just two old words paired to flatter a genuine rarity.