The story
- Old Norse · derived frombólgna
- Middle English · inherited frombolnen
- English todayboln
From Middle English bolnen, bollen, from Old Norse bólgna, from bolginn (“swollen”), past participle of a verb represented by Old English belgan (“to swell”). Compare Swedish bulna (“to swell, be swollen”), Danish bolne (“to swell, be swollen”). Related to belly, bellows.
Etymology from Wiktionary, CC BY-SA 4.0.