eightfold

Eightfold is an English adjective meaning consisting of eight parts or folds. It is formed from the numeral eight and the noun fold, with the sense of a division or repetition arranged eight times. In general usage, eightfold indicates that a value is eight times as large as another (eightfold increase) or that something has eight layers or components.

In geometry and related fields, eightfold describes symmetry or coverage associated with the number eight. Eightfold rotational symmetry, for example, refers to an object that is invariant under rotation by 360/8 = 45 degrees. The concept also appears in descriptions of octagonal structures and other eight-part divisions.

In specialized uses, eightfold appears in well-known phrases and classifications. The Eightfold Path is a central concept in Buddhism, naming eight elements of a path toward ethical and mental development. The Eightfold Way, introduced in the 1960s by Murray Gell-Mann and Kazuhiko Nishijima, is a classification scheme for hadrons in particle physics.

Etymology: the term derives from combining eight with fold, reflecting the sense of being divided into eight parts.