Þríærr

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

þríærr

a. three years old.

Possible runic inscription in Younger Futhark:ᚦᚱᛁᛅᚱᚱ

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