Gjallar
Gjallar is a term from Old Norse that is most commonly encountered as part of the name Gjallarhorn, the horn of the god Heimdallr in Norse mythology. The root gjalla or gjall- is associated with loud calling or roaring, and appears in various Germanic languages with the sense of shouting or thunderous sound. The exact etymology is uncertain, but the element in Gjallarhorn is interpreted as indicating a loud, resonant sound.
In Norse myth, Gjallarhorn is described as a magical horn kept by Heimdallr at Himinbjǫrg, at the
Beyond the compound Gjallarhorn, Gjallar as an independent term is not widely attested in surviving mythic
See also: Gjallarhorn; Heimdallr; Ragnarök; Old Norse language. References to primary sources include the Prose Edda