(French: "ordinary temperament")
A closed 12-note tuning, designed specifically for application to keyboards, which may be viewed as a variant of the well-temperament concept. It arose and became popular in France during the 1600s; a good example is the tuning designed by Chaumont.
A temperament ordinaire generally has most of its "5ths" tuned narrower than "pure" (i.e., the 3:2 ratio) as in 1/4-comma meantone, then a few "5ths" tuned wider than "pure" by some fraction of the syntonic comma.
This is contrasted with a well-temperament, where most "5ths" are tuned pure and some are narrowed by a fraction of the pythagorean comma.