Iðukast

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

iðukast

n. whirling eddy, = iða.

Possible runic inscription in Younger Futhark:ᛁᚦᚢᚴᛅᛋᛏ

Also available in related dictionaries:

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

• Old Norwegian - Johan Fritzner's Dictionary