The phrase temperament ordinaire (French tempérament ordinaire, meaning literally "ordinary temperament" or "usual temperament") is a term for musical intonation, particularly the tempered tuning of keyboard instruments. In modern usage, it usually refers to temperaments falling within the range (as understood broadly) of tunings now known as "well-tempered".
The expression occurs primarily in French-language works of the 17th and 18th centuries concerning theory and practice of musical intonation with regard to keyboard instruments.[1][2] It is discussed again, in the same or a similar musical application, in modern literature concerned with historical practices relating to keyboard instruments and performance.