Runes are the letters in a set of related alphabets known as runic alphabets which were used to write various Germanic languages before the adoption of the Latin alphabet and for specialized purposes thereafter. The Scandinavian variants are also known as futhark or fuþark (derived from their first six letters of the alphabet: F, U, Þ, A, R, and K); the Anglo-Saxon variant is futhorc or fuþorc (due to sound changes undergone in Old English by the same six letters). Runology is the study of the runic alphabets, runic inscriptions, runestones, and their history. Runology forms a specialized branch of Germanic linguistics.

The earliest runic inscriptions date from around AD 150. The characters were generally replaced by the Latin alphabet as the cultures that had used runes underwent Christianization by around AD 700 in central Europe and by around AD 1100 in Northern Europe. However, the use of runes persisted for specialized purposes in Northern Europe. Until the early 20th century runes were used in rural Sweden for decoration purposes in Dalarna and on Runic calendars.