bhad- / Indo-European roots
1. better1 from Old English betera, better, from Germanic (comparative) *batizō.
2. best from Old English bet(e)st, best, from Germanic (superlative) *batistaz.
3. boot2 from Old English bōt, remedy, aid, from Germanic noun *bōtō.
4. batten1 ultimately from Old Norse batna, to improve, from Germanic verb *batnan, to become better.
[Pokorny bhā̆d- 106.]