Ásbrú

As defined by A Concise Dictionary of Old Icelandic (Geir Zoëga):

ásbrú

f. bridge of the Gods, the rainbow.

Possible runic inscription in Younger Futhark:ᛅᛋᛒᚱᚢ

Also available in related dictionaries:

This headword also appears in dictionaries of other languages closely related to Old Icelandic.

• Old Norse - Cleasby & Vigfusson Dictionary