Þykkna

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

þykkna

(að), v. to thicken, become thick (tók veðrit at ~).

Possible runic inscription in Younger Futhark:ᚦᚢᚴᚴᚾᛅ

Also available in related dictionaries:

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

• Old Norse - Cleasby & Vigfusson Dictionary
• Old Norwegian - Johan Fritzner's Dictionary