Þrjú

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

þrjú

from þrír, three.

Possible runic inscription in Younger Futhark:ᚦᚱᛁᚢ

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