The American Heritage® Dictionary of the English Language: Fourth Edition. 2000.
Appendix I
Indo-European Roots
ENTRY:
bhl-
DEFINITION:
To blow. Contracted from *bhle1-, or possibly lengthened grade *bhl2- from alternative root *bhle2-. Possibly identical to bhel-3II*bhl- above. Derivatives include blaze, flatus, and flavor. 1.blow1, from Old English blwan, to blow, from Germanic suffixed form *bl-w-.2a.bladder, from Old English bldre, blister, bladder; b.blather, from Old Norse bladhra (noun), bladder, and bladhra (verb), to prattle. Both a and b from Germanic suffixed form *bldram, something blown up. 3a.blast, from Old English blst, a blowing, blast; b.isinglass, from Middle Dutch blas(e), a bladder; c.blasé, blaze3, from Middle Dutch blsen, to blow up, swell. ac all from Germanic extended form *bls-.4. Zero-grade form *bh- (> *bhl-). flabellum, flageolet, flatulent, flatus, flavor; afflatus, conflate, deflate, inflate, insufflate, soufflé, from Latin flre, to blow. (In Pokorny 3. bhel- 120.)