More about Bifrost
Bifrost “the rainbow bridge of the gods” may look at first glance like a compound of Latin bi- “twice” and English frost, but it should come as little surprise that the name is of Old Norse origin instead. Old Norse is the ancestral language of Danish, Icelandic, Norwegian, and Swedish, and it was spoken throughout northern Europe 1000 years ago. In Old Norse, Bifrost (more accurately transliterated as Bifrǫst or Bifröst) is likely equivalent to bifa “to shake” and rǫst “league” or, more directly, “measure of length between two places of rest.” Old Norse and English are both Germanic languages, and while bifa does not have any relatives in modern English (except obsolete bive “to shake”), rǫst is cognate to English rest. Bifrost was first recorded in English in the late 18th century.