eighth

Eighth is the ordinal form of the number eight. It denotes the position of an item in a sequence when counting from one. It is formed by appending the ordinal suffix -th to the cardinal eight. Eighth is used in dates, rankings, and legal designations. Etymology: from Old English eahta with the suffix -th; related forms in other Germanic languages.

In mathematics and measurement, an eighth refers to the fraction 1/8, equal to 0.125. It is used to subdivide quantities into eight equal parts, in cooking, geometry, and statistics.

In music, the term eighth describes an eighth note, or quaver in British English. Its duration is one-half the length of a quarter note; two eighth notes equal one quarter note. Eighth notes are commonly beamed in pairs or groups to indicate rhythmic subdivision.

Calendar and language: In the historical Roman calendar, October’s name means eighth month; the names September through December reflect seven to ten. In modern usage, October is the tenth month, but the historic eight-month origin remains reflected in the names of the months and in ordinal forms such as eighth.

Notable uses include the Eighth Amendment to the United States Constitution, which prohibits cruel and unusual punishment, and the Eighth Air Force, a major United States Army Air Forces unit in World War II. The term eighth also appears in the names of various organizations or subdivisions that are designated as the eighth unit within a larger structure.