in Music, that property of sounds by which they may become tones, i.e., may differ from each other in gravity and acuteness. The intonation of a singer will be true or false, according to the observance or non-observance of the just proportions that belong to the intervals sung. The intonation of an organ, or a piano, will be false if the instrument has been ill tuned. So of a violin, &c., if the player has not the skill necessary to stop the notes in time on the finger-board. False intonation is the rule, true intonation the rare exception among singers, and also among players on bowed instruments, such as the violin, violoncello, &c. Intonation, or intoning, is also applied to the singing of certain chants, or portions of chants, in the service of the Roman Church.