Definition of "rune"

rune

/ɹuːn/

noun
plural runes
1. A letter, or character, used in the written language of various ancient Germanic peoples, especially the Scandinavians and the Anglo-Saxons.
  Quotations
  "Finding you somewhere to live isn't going to be easy," he said. "We must cast the runes," said Catweazle. "They will tell us."
  1971, Richard Carpenter, Catweazle and the Magic Zodiac, Harmondsworth: Puffin Books, page 32
2. A Finnic or Scandinavian epic poem, or a division of one, especially a division of the Kalevala.
3. A letter or mark used as a mystical or magic symbol.
  Quotations
  "Are the, um, eldritch runes supposed to glow like that?" "Dunno. I asked the distributor about 'em and he started shaking really fast like in a Tool video."
  2016, Jeph Jacques, Questionable Content (webcomic), Number 3242: The Dunkelest Brau
4. A verse or song, especially one with mystical or mysterious overtones; a spell or an incantation.
  Quotations
  the fiddle sang and sang as ceaselessly as the chanting cicada without, and the frogs intoning their sylvan runes by the waterside.
  1891, Mary Noailles Murfree, In the "Stranger People's" Country, Nebraska, published 2005, page 15
5. (obsolete) Alternative form of roun (“secret or mystery”).
6. (programming, in the Go programming language) A Unicode code point.
  Quotations
  Go language defines the type rune as an alias for the type int32 to represent a Unicode code point. A string in Go is a sequence of runes.
  2016, Shiju Varghese, Go Recipes, Apress, page 12