ninth

Ninth is the ordinal form of the number nine, used to denote position in a sequence. It follows eighth and precedes tenth. In English, the form is created by adding the suffix -th to the cardinal nine, with the spelling reflecting the pronunciation /naɪnθ/.

In mathematics and general usage, ninth can refer to the ninth item in any ordered set, or to the value nine itself when counted in a sequence. The term appears in various fields to indicate a specific rank or position.

In music, the ninth is an interval that spans an octave plus a second, and ninth chords add a ninth above the root. Major ninths and minor ninths are common in jazz and other modern styles, and they can be used to create extended harmonies and color in progressions.

In the calendar, September is the ninth month in the modern Gregorian calendar. Its name derives from Latin septem, meaning seven, because it was the seventh month in the early Roman calendar before January and February were added, shifting the months we now use.

In law and government, the Ninth Amendment to the United States Constitution protects rights not enumerated in the Constitution, reinforcing the idea that people retain rights beyond those listed in the Bill of Rights.

Notable uses of the term include Beethoven's Ninth Symphony, completed in 1824, a landmark work in classical music. The ordinal ninth appears widely in culture, science, and daily language as a way to designate the next position after the eighth item.