Entry 2 senses · 2 variants Webster, 1913 Boln · IPA /boʊln/ v. i. a. 01 v. i. To swell; to puff. 1. To swell; to puff. 02 a. Swollen; puffed out. 1. Swollen; puffed out. “Thin, and boln out like a sail.” — B. Jonson.