rune

noun

1. A letter, or character, used in the written language of various ancient Germanic peoples, especially the Scandinavians and the Anglo-Saxons.

   “Yet they made for man those mystic swords of superhuman workmanship engraved with magic runes and dipped when red hot in blood or in a broth of poisonous herbs and twigs.”

   “Runes were the letters of an ancient Germanic alphabet, ultimately derived from the Mediterranean alphabets, which was used for carving on wood or stone and which to some extent survived the introduction of writing.”

2. Any visually similar script, such as Hungarian runes (the Old Hungarian script) or Turkic runes (the Old Turkic script).
3. A Finnic or Scandinavian epic poem, or a division of one, especially a division of the Kalevala.
4. A letter or mark used as a mystical or magic symbol.

   “And the sword that had visited Earth from so far away smote like the falling of thunderbolts [...] and the runes in Alveric’s far-travelled sword exulted, and roared at the elf-knight; until in the dark of the wood, amongst branches severed from disenchanted trees, with a blow like that of a thunderbolt riving an oak-tree, Alveric slew him.”

   “"Finding you somewhere to live isn't going to be easy," he said. "We must cast the runes," said Catweazle. "They will tell us."”

   “"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."”

5. A verse or song, especially one with mystical or mysterious overtones; a spell or an incantation.

   “Where the daylight peeps thro' like the glint of the Moon, / And the branches are rustling a murmurous rune, / The Owls sit in council like prophets of Fate, / Discussing grave questions of Kingdom and State.”

   “the fiddle sang and sang as ceaselessly as the chanting cicada without, and the frogs intoning their sylvan runes by the waterside.”

6. (alt-of, alternative, obsolete)Alternative form of roun (“secret or mystery”).
7. A Unicode code point.

   “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.”

verb

1. (dated, intransitive, poetic)To compose or perform poetry or songs.