Etymology in the sources
Source-reportedAccording to Otterbjörk, originally a byname, from þróndr (“man from Trøndelag (a region in Norway)”). According to Vågslid, from the stem of the Old Norse verb þróask (“to prosper”).
Sources for this account (2)
- Wiktionary: ÞróndrCC-BY-SA-4.0 · retrieved 2026-10-15
- Polish Wiktionary: ÞróndrCC-BY-SA-4.0 · retrieved 2026-10-14

