sixtyfourth

Sixtyfourth is the ordinal form representing the position of an item in a sequence of sixty-four items. In standard English, the usual spelling is sixty-fourth, with a hyphen between sixty and four and the suffix -th. The unhyphenated variant sixtyfourth is uncommon in formal writing and may appear in computer-related contexts where hyphens are not used.

In mathematics and measurements, sixty-fourth denotes a fraction with denominator 64, as in one sixty-fourth (1/64) or multiple sixty-fourths (for example, three sixty-fourths). As an ordinal, it can describe progress through a set of sixty-four elements or steps, such as a sixty-fourth item in a list or a sixty-fourth position in a race.

In music notation, a sixty-fourth note is a very short duration, equal to 1/64 of a whole note; it is typically written as a 64th note. The term is part of a system of note values that also includes eighth, sixteenth, and thirty-second notes.

Etymology and orthography: 'sixty' and 'four' form the compound base, with the -th suffix marking ordinality. Standards for hyphenation vary by style guide and region, but hyphenation is common in formal writing.

See also: sixty-third, sixty-fifth, fractional notation, 64 (number).